gt:             throw newIllegalArgumentException("void type");
context: /*
   * Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package java.lang.invoke;
  
  import java.lang.reflect.*;
  import sun.invoke.util.ValueConversions;
  import sun.invoke.util.VerifyAccess;
  import sun.invoke.util.Wrapper;
  import java.util.List;
  import java.util.ArrayList;
  import java.util.Arrays;
  import sun.reflect.CallerSensitive;
  import sun.reflect.Reflection;
  import sun.reflect.misc.ReflectUtil;
  import static java.lang.invoke.MethodHandleStatics.*;
  import static java.lang.invoke.MethodHandleNatives.Constants.*;
  import sun.security.util.SecurityConstants;
  
  /**
   * This class consists exclusively of static methods that operate on or return
   * method handles. They fall into several categories:
   * <ul>
   * <li>Lookup methods which help create method handles for methods and fields.
   * <li>Combinator methods, which combine or transform pre-existing method handles into new ones.
   * <li>Other factory methods to create method handles that emulate other common JVM operations or control flow patterns.
   * <li>Wrapper methods which can convert between method handles and interface types.
   * </ul>
   * <p>
   * @author John Rose, JSR 292 EG
   */
  public class MethodHandles {
  
      private MethodHandles() { }  // do not instantiate
  
      private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
      static { MethodHandleImpl.initStatics(); }
      // See IMPL_LOOKUP below.
  
      //// Method handle creation from ordinary methods.
  
      /**
       * Returns a {@link Lookup lookup object} on the caller,
       * which has the capability to access any method handle that the caller has access to,
       * including direct method handles to private fields and methods.
       * This lookup object is a <em>capability</em> which may be delegated to trusted agents.
       * Do not store it in place where untrusted code can access it.
       */
      @CallerSensitive
      public static Lookup lookup() {
          return new Lookup(Reflection.getCallerClass());
      }
  
      /**
       * Returns a {@link Lookup lookup object} which is trusted minimally.
       * It can only be used to create method handles to
       * publicly accessible fields and methods.
       * <p>
       * As a matter of pure convention, the {@linkplain Lookup#lookupClass lookup class}
       * of this lookup object will be {@link java.lang.Object}.
       * <p>
       * The lookup class can be changed to any other class {@code C} using an expression of the form
       * {@linkplain Lookup#in <code>publicLookup().in(C.class)</code>}.
       * Since all classes have equal access to public names,
       * such a change would confer no new access rights.
       */
      public static Lookup publicLookup() {
          return Lookup.PUBLIC_LOOKUP;
      }
  
      /**
       * A <em>lookup object</em> is a factory for creating method handles,
       * when the creation requires access checking.
       * Method handles do not perform
       * access checks when they are called, but rather when they are created.
       * Therefore, method handle access
       * restrictions must be enforced when a method handle is created.
       * The caller class against which those restrictions are enforced
       * is known as the {@linkplain #lookupClass lookup class}.
       * <p>
       * A lookup class which needs to create method handles will call
       * {@link MethodHandles#lookup MethodHandles.lookup} to create a factory for itself.
       * When the {@code Lookup} factory object is created, the identity of the lookup class is
       * determined, and securely stored in the {@code Lookup} object.
       * The lookup class (or its delegates) may then use factory methods
       * on the {@code Lookup} object to create method handles for access-checked members.
       * This includes all methods, constructors, and fields which are allowed to the lookup class,
       * even private ones.
       * <p>
       * The factory methods on a {@code Lookup} object correspond to all major
       * use cases for methods, constructors, and fields.
       * Here is a summary of the correspondence between these factory methods and
       * the behavior the resulting method handles:
       * <code>
       * <table border=1 cellpadding=5 summary="lookup method behaviors">
       * <tr><th>lookup expression</th><th>member</th><th>behavior</th></tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#findGetter lookup.findGetter(C.class,"f",FT.class)}</td>
       *     <td>FT f;</td><td>(T) this.f;</td>
       * </tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#findStaticGetter lookup.findStaticGetter(C.class,"f",FT.class)}</td>
       *     <td>static<br>FT f;</td><td>(T) C.f;</td>
       * </tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#findSetter lookup.findSetter(C.class,"f",FT.class)}</td>
       *     <td>FT f;</td><td>this.f = x;</td>
       * </tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#findStaticSetter lookup.findStaticSetter(C.class,"f",FT.class)}</td>
       *     <td>static<br>FT f;</td><td>C.f = arg;</td>
       * </tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#findVirtual lookup.findVirtual(C.class,"m",MT)}</td>
       *     <td>T m(A*);</td><td>(T) this.m(arg*);</td>
       * </tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#findStatic lookup.findStatic(C.class,"m",MT)}</td>
       *     <td>static<br>T m(A*);</td><td>(T) C.m(arg*);</td>
       * </tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#findSpecial lookup.findSpecial(C.class,"m",MT,this.class)}</td>
       *     <td>T m(A*);</td><td>(T) super.m(arg*);</td>
       * </tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#findConstructor lookup.findConstructor(C.class,MT)}</td>
       *     <td>C(A*);</td><td>(T) new C(arg*);</td>
       * </tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#unreflectGetter lookup.unreflectGetter(aField)}</td>
       *     <td>(static)?<br>FT f;</td><td>(FT) aField.get(thisOrNull);</td>
       * </tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#unreflectSetter lookup.unreflectSetter(aField)}</td>
       *     <td>(static)?<br>FT f;</td><td>aField.set(thisOrNull, arg);</td>
       * </tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#unreflect lookup.unreflect(aMethod)}</td>
       *     <td>(static)?<br>T m(A*);</td><td>(T) aMethod.invoke(thisOrNull, arg*);</td>
       * </tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#unreflectConstructor lookup.unreflectConstructor(aConstructor)}</td>
       *     <td>C(A*);</td><td>(C) aConstructor.newInstance(arg*);</td>
       * </tr>
       * <tr>
       *     <td>{@linkplain java.lang.invoke.MethodHandles.Lookup#unreflect lookup.unreflect(aMethod)}</td>
       *     <td>(static)?<br>T m(A*);</td><td>(T) aMethod.invoke(thisOrNull, arg*);</td>
       * </tr>
       * </table>
       * </code>
       * Here, the type {@code C} is the class or interface being searched for a member,
       * documented as a parameter named {@code refc} in the lookup methods.
       * The method or constructor type {@code MT} is composed from the return type {@code T}
       * and the sequence of argument types {@code A*}.
       * Both {@code MT} and the field type {@code FT} are documented as a parameter named {@code type}.
       * The formal parameter {@code this} stands for the self-reference of type {@code C};
       * if it is present, it is always the leading argument to the method handle invocation.
       * (In the case of some {@code protected} members, {@code this} may be
       * restricted in type to the lookup class; see below.)
       * The name {@code arg} stands for all the other method handle arguments.
       * In the code examples for the Core Reflection API, the name {@code thisOrNull}
       * stands for a null reference if the accessed method or field is static,
       * and {@code this} otherwise.
       * The names {@code aMethod}, {@code aField}, and {@code aConstructor} stand
       * for reflective objects corresponding to the given members.
       * <p>
       * In cases where the given member is of variable arity (i.e., a method or constructor)
       * the returned method handle will also be of {@linkplain MethodHandle#asVarargsCollector variable arity}.
       * In all other cases, the returned method handle will be of fixed arity.
       * <p>
       * The equivalence between looked-up method handles and underlying
       * class members can break down in a few ways:
       * <ul>
       * <li>If {@code C} is not symbolically accessible from the lookup class's loader,
       * the lookup can still succeed, even when there is no equivalent
       * Java expression or bytecoded constant.
       * <li>Likewise, if {@code T} or {@code MT}
       * is not symbolically accessible from the lookup class's loader,
       * the lookup can still succeed.
       * For example, lookups for {@code MethodHandle.invokeExact} and
       * {@code MethodHandle.invoke} will always succeed, regardless of requested type.
       * <li>If there is a security manager installed, it can forbid the lookup
       * on various grounds (<a href="#secmgr">see below</a>).
       * By contrast, the {@code ldc} instruction is not subject to
       * security manager checks.
       * </ul>
       *
       * <h3><a name="access"></a>Access checking</h3>
       * Access checks are applied in the factory methods of {@code Lookup},
       * when a method handle is created.
       * This is a key difference from the Core Reflection API, since
       * {@link java.lang.reflect.Method#invoke java.lang.reflect.Method.invoke}
       * performs access checking against every caller, on every call.
       * <p>
       * All access checks start from a {@code Lookup} object, which
       * compares its recorded lookup class against all requests to
       * create method handles.
       * A single {@code Lookup} object can be used to create any number
       * of access-checked method handles, all checked against a single
       * lookup class.
       * <p>
       * A {@code Lookup} object can be shared with other trusted code,
       * such as a metaobject protocol.
       * A shared {@code Lookup} object delegates the capability
       * to create method handles on private members of the lookup class.
       * Even if privileged code uses the {@code Lookup} object,
       * the access checking is confined to the privileges of the
       * original lookup class.
       * <p>
       * A lookup can fail, because
       * the containing class is not accessible to the lookup class, or
       * because the desired class member is missing, or because the
       * desired class member is not accessible to the lookup class.
       * In any of these cases, a {@code ReflectiveOperationException} will be
       * thrown from the attempted lookup.  The exact class will be one of
       * the following:
       * <ul>
       * <li>NoSuchMethodException &mdash; if a method is requested but does not exist
       * <li>NoSuchFieldException &mdash; if a field is requested but does not exist
       * <li>IllegalAccessException &mdash; if the member exists but an access check fails
       * </ul>
       * <p>
       * In general, the conditions under which a method handle may be
       * looked up for a method {@code M} are exactly equivalent to the conditions
       * under which the lookup class could have compiled and resolved a call to {@code M}.
       * And the effect of invoking the method handle resulting from the lookup
       * is exactly equivalent to executing the compiled and resolved call to {@code M}.
       * The same point is true of fields and constructors.
       * <p>
       * If the desired member is {@code protected}, the usual JVM rules apply,
       * including the requirement that the lookup class must be either be in the
       * same package as the desired member, or must inherit that member.
       * (See the Java Virtual Machine Specification, sections 4.9.2, 5.4.3.5, and 6.4.)
       * In addition, if the desired member is a non-static field or method
       * in a different package, the resulting method handle may only be applied
       * to objects of the lookup class or one of its subclasses.
       * This requirement is enforced by narrowing the type of the leading
       * {@code this} parameter from {@code C}
       * (which will necessarily be a superclass of the lookup class)
       * to the lookup class itself.
       * <p>
       * In some cases, access between nested classes is obtained by the Java compiler by creating
       * an wrapper method to access a private method of another class
       * in the same top-level declaration.
       * For example, a nested class {@code C.D}
       * can access private members within other related classes such as
       * {@code C}, {@code C.D.E}, or {@code C.B},
       * but the Java compiler may need to generate wrapper methods in
       * those related classes.  In such cases, a {@code Lookup} object on
       * {@code C.E} would be unable to those private members.
       * A workaround for this limitation is the {@link Lookup#in Lookup.in} method,
       * which can transform a lookup on {@code C.E} into one on any of those other
       * classes, without special elevation of privilege.
       * <p>
       * Although bytecode instructions can only refer to classes in
       * a related class loader, this API can search for methods in any
       * class, as long as a reference to its {@code Class} object is
       * available.  Such cross-loader references are also possible with the
       * Core Reflection API, and are impossible to bytecode instructions
       * such as {@code invokestatic} or {@code getfield}.
       * There is a {@linkplain java.lang.SecurityManager security manager API}
       * to allow applications to check such cross-loader references.
       * These checks apply to both the {@code MethodHandles.Lookup} API
       * and the Core Reflection API
       * (as found on {@link java.lang.Class Class}).
       * <p>
       * Access checks only apply to named and reflected methods,
       * constructors, and fields.
       * Other method handle creation methods, such as
       * {@link MethodHandle#asType MethodHandle.asType},
       * do not require any access checks, and are done
       * with static methods of {@link MethodHandles},
       * independently of any {@code Lookup} object.
       *
       * <h3>Security manager interactions</h3>
       * <a name="secmgr"></a>
       * If a security manager is present, member lookups are subject to
       * additional checks.
       * From one to four calls are made to the security manager.
       * Any of these calls can refuse access by throwing a
       * {@link java.lang.SecurityException SecurityException}.
       * Define {@code smgr} as the security manager,
       * {@code refc} as the containing class in which the member
       * is being sought, and {@code defc} as the class in which the
       * member is actually defined.
       * The calls are made according to the following rules:
       * <ul>
       * <li>In all cases, {@link SecurityManager#checkMemberAccess
       *     smgr.checkMemberAccess(refc, Member.PUBLIC)} is called.
       * <li>If the class loader of the lookup class is not
       *     the same as or an ancestor of the class loader of {@code refc},
       *     then {@link SecurityManager#checkPackageAccess
       *     smgr.checkPackageAccess(refcPkg)} is called,
       *     where {@code refcPkg} is the package of {@code refc}.
       * <li>If the retrieved member is not public,
       *     {@link SecurityManager#checkMemberAccess
       *     smgr.checkMemberAccess(defc, Member.DECLARED)} is called.
       *     (Note that {@code defc} might be the same as {@code refc}.)
       *     The default implementation of this security manager method
       *     inspects the stack to determine the original caller of
       *     the reflective request (such as {@code findStatic}),
       *     and performs additional permission checks if the
       *     class loader of {@code defc} differs from the class
       *     loader of the class from which the reflective request came.
       * <li>If the retrieved member is not public,
       *     and if {@code defc} and {@code refc} are in different class loaders,
       *     and if the class loader of the lookup class is not
       *     the same as or an ancestor of the class loader of {@code defc},
       *     then {@link SecurityManager#checkPackageAccess
       *     smgr.checkPackageAccess(defcPkg)} is called,
       *     where {@code defcPkg} is the package of {@code defc}.
       * </ul>
       */
      public static final
      class Lookup {
          /** The class on behalf of whom the lookup is being performed. */
          private final Class<?> lookupClass;
  
          /** The allowed sorts of members which may be looked up (PUBLIC, etc.). */
          private final int allowedModes;
  
          /** A single-bit mask representing {@code public} access,
           *  which may contribute to the result of {@link #lookupModes lookupModes}.
           *  The value, {@code 0x01}, happens to be the same as the value of the
           *  {@code public} {@linkplain java.lang.reflect.Modifier#PUBLIC modifier bit}.
           */
          public static final int PUBLIC = Modifier.PUBLIC;
  
          /** A single-bit mask representing {@code private} access,
           *  which may contribute to the result of {@link #lookupModes lookupModes}.
           *  The value, {@code 0x02}, happens to be the same as the value of the
           *  {@code private} {@linkplain java.lang.reflect.Modifier#PRIVATE modifier bit}.
           */
          public static final int PRIVATE = Modifier.PRIVATE;
  
          /** A single-bit mask representing {@code protected} access,
           *  which may contribute to the result of {@link #lookupModes lookupModes}.
           *  The value, {@code 0x04}, happens to be the same as the value of the
           *  {@code protected} {@linkplain java.lang.reflect.Modifier#PROTECTED modifier bit}.
           */
          public static final int PROTECTED = Modifier.PROTECTED;
  
          /** A single-bit mask representing {@code package} access (default access),
           *  which may contribute to the result of {@link #lookupModes lookupModes}.
           *  The value is {@code 0x08}, which does not correspond meaningfully to
           *  any particular {@linkplain java.lang.reflect.Modifier modifier bit}.
           */
          public static final int PACKAGE = Modifier.STATIC;
  
          private static final int ALL_MODES = (PUBLIC | PRIVATE | PROTECTED | PACKAGE);
          private static final int TRUSTED   = -1;
  
          private static int fixmods(int mods) {
              mods &= (ALL_MODES - PACKAGE);
              return (mods != 0) ? mods : PACKAGE;
          }
  
          /** Tells which class is performing the lookup.  It is this class against
           *  which checks are performed for visibility and access permissions.
           *  <p>
           *  The class implies a maximum level of access permission,
           *  but the permissions may be additionally limited by the bitmask
           *  {@link #lookupModes lookupModes}, which controls whether non-public members
           *  can be accessed.
           */
          public Class<?> lookupClass() {
              return lookupClass;
          }
  
          // This is just for calling out to MethodHandleImpl.
          private Class<?> lookupClassOrNull() {
              return (allowedModes == TRUSTED) ? null : lookupClass;
          }
  
          /** Tells which access-protection classes of members this lookup object can produce.
           *  The result is a bit-mask of the bits
           *  {@linkplain #PUBLIC PUBLIC (0x01)},
           *  {@linkplain #PRIVATE PRIVATE (0x02)},
           *  {@linkplain #PROTECTED PROTECTED (0x04)},
           *  and {@linkplain #PACKAGE PACKAGE (0x08)}.
           *  <p>
           *  A freshly-created lookup object
           *  on the {@linkplain java.lang.invoke.MethodHandles#lookup() caller's class}
           *  has all possible bits set, since the caller class can access all its own members.
           *  A lookup object on a new lookup class
           *  {@linkplain java.lang.invoke.MethodHandles.Lookup#in created from a previous lookup object}
           *  may have some mode bits set to zero.
           *  The purpose of this is to restrict access via the new lookup object,
           *  so that it can access only names which can be reached by the original
           *  lookup object, and also by the new lookup class.
           */
          public int lookupModes() {
              return allowedModes & ALL_MODES;
          }
  
          /** Embody the current class (the lookupClass) as a lookup class
           * for method handle creation.
           * Must be called by from a method in this package,
           * which in turn is called by a method not in this package.
           * <p>
           * Also, don't make it private, lest javac interpose
           * an access$N method.
           */
  
          Lookup(Class<?> lookupClass) {
              this(lookupClass, ALL_MODES);
              checkUnprivilegedlookupClass(lookupClass, ALL_MODES);
          }
  
          private Lookup(Class<?> lookupClass, int allowedModes) {
              this.lookupClass = lookupClass;
              this.allowedModes = allowedModes;
          }
  
          /**
           * Creates a lookup on the specified new lookup class.
           * The resulting object will report the specified
           * class as its own {@link #lookupClass lookupClass}.
           * <p>
           * However, the resulting {@code Lookup} object is guaranteed
           * to have no more access capabilities than the original.
           * In particular, access capabilities can be lost as follows:<ul>
           * <li>If the new lookup class differs from the old one,
           * protected members will not be accessible by virtue of inheritance.
           * (Protected members may continue to be accessible because of package sharing.)
           * <li>If the new lookup class is in a different package
           * than the old one, protected and default (package) members will not be accessible.
           * <li>If the new lookup class is not within the same package member
           * as the old one, private members will not be accessible.
           * <li>If the new lookup class is not accessible to the old lookup class,
           * then no members, not even public members, will be accessible.
           * (In all other cases, public members will continue to be accessible.)
           * </ul>
           *
           * @param requestedLookupClass the desired lookup class for the new lookup object
           * @return a lookup object which reports the desired lookup class
           * @throws NullPointerException if the argument is null
           */
          public Lookup in(Class<?> requestedLookupClass) {
              requestedLookupClass.getClass();  // null check
              if (allowedModes == TRUSTED)  // IMPL_LOOKUP can make any lookup at all
                  return new Lookup(requestedLookupClass, ALL_MODES);
              if (requestedLookupClass == this.lookupClass)
                  return this;  // keep same capabilities
              int newModes = (allowedModes & (ALL_MODES & ~PROTECTED));
              if ((newModes & PACKAGE) != 0
                  && !VerifyAccess.isSamePackage(this.lookupClass, requestedLookupClass)) {
                  newModes &= ~(PACKAGE|PRIVATE);
              }
              // Allow nestmate lookups to be created without special privilege:
              if ((newModes & PRIVATE) != 0
                  && !VerifyAccess.isSamePackageMember(this.lookupClass, requestedLookupClass)) {
                  newModes &= ~PRIVATE;
              }
              if ((newModes & PUBLIC) != 0
                  && !VerifyAccess.isClassAccessible(requestedLookupClass, this.lookupClass, allowedModes)) {
                  // The requested class it not accessible from the lookup class.
                  // No permissions.
                  newModes = 0;
              }
              checkUnprivilegedlookupClass(requestedLookupClass, newModes);
              return new Lookup(requestedLookupClass, newModes);
          }
  
          // Make sure outer class is initialized first.
          static { IMPL_NAMES.getClass(); }
  
          /** Version of lookup which is trusted minimally.
           *  It can only be used to create method handles to
           *  publicly accessible members.
           */
          static final Lookup PUBLIC_LOOKUP = new Lookup(Object.class, PUBLIC);
  
          /** Package-private version of lookup which is trusted. */
          static final Lookup IMPL_LOOKUP = new Lookup(Object.class, TRUSTED);
  
          private static void checkUnprivilegedlookupClass(Class<?> lookupClass, int allowedModes) {
              String name = lookupClass.getName();
              if (name.startsWith("java.lang.invoke."))
                  throw newIllegalArgumentException("illegal lookupClass: "+lookupClass);
  
              // For caller-sensitive MethodHandles.lookup()
              // disallow lookup more restricted packages
              if (allowedModes == ALL_MODES && lookupClass.getClassLoader() == null) {
                  if (name.startsWith("java.") ||
                          (name.startsWith("sun.") && !name.startsWith("sun.invoke."))) {
                      throw newIllegalArgumentException("illegal lookupClass: " + lookupClass);
                  }
              }
          }
  
          /**
           * Displays the name of the class from which lookups are to be made.
           * (The name is the one reported by {@link java.lang.Class#getName() Class.getName}.)
           * If there are restrictions on the access permitted to this lookup,
           * this is indicated by adding a suffix to the class name, consisting
           * of a slash and a keyword.  The keyword represents the strongest
           * allowed access, and is chosen as follows:
           * <ul>
           * <li>If no access is allowed, the suffix is "/noaccess".
           * <li>If only public access is allowed, the suffix is "/public".
           * <li>If only public and package access are allowed, the suffix is "/package".
           * <li>If only public, package, and private access are allowed, the suffix is "/private".
           * </ul>
           * If none of the above cases apply, it is the case that full
           * access (public, package, private, and protected) is allowed.
           * In this case, no suffix is added.
           * This is true only of an object obtained originally from
           * {@link java.lang.invoke.MethodHandles#lookup MethodHandles.lookup}.
           * Objects created by {@link java.lang.invoke.MethodHandles.Lookup#in Lookup.in}
           * always have restricted access, and will display a suffix.
           * <p>
           * (It may seem strange that protected access should be
           * stronger than private access.  Viewed independently from
           * package access, protected access is the first to be lost,
           * because it requires a direct subclass relationship between
           * caller and callee.)
           * @see #in
           */
          @Override
          public String toString() {
              String cname = lookupClass.getName();
              switch (allowedModes) {
              case 0:  // no privileges
                  return cname + "/noaccess";
              case PUBLIC:
                  return cname + "/public";
              case PUBLIC|PACKAGE:
                  return cname + "/package";
              case ALL_MODES & ~PROTECTED:
                  return cname + "/private";
              case ALL_MODES:
                  return cname;
              case TRUSTED:
                  return "/trusted";  // internal only; not exported
              default:  // Should not happen, but it's a bitfield...
                  cname = cname + "/" + Integer.toHexString(allowedModes);
                  assert(false) : cname;
                  return cname;
              }
          }
  
          /**
           * Produces a method handle for a static method.
           * The type of the method handle will be that of the method.
           * (Since static methods do not take receivers, there is no
           * additional receiver argument inserted into the method handle type,
           * as there would be with {@link #findVirtual findVirtual} or {@link #findSpecial findSpecial}.)
           * The method and all its argument types must be accessible to the lookup class.
           * If the method's class has not yet been initialized, that is done
           * immediately, before the method handle is returned.
           * <p>
           * The returned method handle will have
           * {@linkplain MethodHandle#asVarargsCollector variable arity} if and only if
           * the method's variable arity modifier bit ({@code 0x0080}) is set.
           * @param refc the class from which the method is accessed
           * @param name the name of the method
           * @param type the type of the method
           * @return the desired method handle
           * @throws NoSuchMethodException if the method does not exist
           * @throws IllegalAccessException if access checking fails,
           *                                or if the method is not {@code static},
           *                                or if the method's variable arity modifier bit
           *                                is set and {@code asVarargsCollector} fails
           * @exception SecurityException if a security manager is present and it
           *                              <a href="MethodHandles.Lookup.html#secmgr">refuses access</a>
           * @throws NullPointerException if any argument is null
           */
          public
          MethodHandle findStatic(Class<?> refc, String name, MethodType type) throws NoSuchMethodException, IllegalAccessException {
              MemberName method = resolveOrFail(REF_invokeStatic, refc, name, type);
              checkSecurityManager(refc, method);
              return getDirectMethod(REF_invokeStatic, refc, method, findBoundCallerClass(method));
          }
  
          /**
           * Produces a method handle for a virtual method.
           * The type of the method handle will be that of the method,
           * with the receiver type (usually {@code refc}) prepended.
           * The method and all its argument types must be accessible to the lookup class.
           * <p>
           * When called, the handle will treat the first argument as a receiver
           * and dispatch on the receiver's type to determine which method
           * implementation to enter.
           * (The dispatching action is identical with that performed by an
           * {@code invokevirtual} or {@code invokeinterface} instruction.)
           * <p>
           * The first argument will be of type {@code refc} if the lookup
           * class has full privileges to access the member.  Otherwise
           * the member must be {@code protected} and the first argument
           * will be restricted in type to the lookup class.
           * <p>
           * The returned method handle will have
           * {@linkplain MethodHandle#asVarargsCollector variable arity} if and only if
           * the method's variable arity modifier bit ({@code 0x0080}) is set.
           * <p>
           * Because of the general equivalence between {@code invokevirtual}
           * instructions and method handles produced by {@code findVirtual},
           * if the class is {@code MethodHandle} and the name string is
           * {@code invokeExact} or {@code invoke}, the resulting
           * method handle is equivalent to one produced by
           * {@link java.lang.invoke.MethodHandles#exactInvoker MethodHandles.exactInvoker} or
           * {@link java.lang.invoke.MethodHandles#invoker MethodHandles.invoker}
           * with the same {@code type} argument.
           *
           * @param refc the class or interface from which the method is accessed
           * @param name the name of the method
           * @param type the type of the method, with the receiver argument omitted
           * @return the desired method handle
           * @throws NoSuchMethodException if the method does not exist
           * @throws IllegalAccessException if access checking fails,
           *                                or if the method is {@code static}
           *                                or if the method's variable arity modifier bit
           *                                is set and {@code asVarargsCollector} fails
           * @exception SecurityException if a security manager is present and it
           *                              <a href="MethodHandles.Lookup.html#secmgr">refuses access</a>
           * @throws NullPointerException if any argument is null
           */
          public MethodHandle findVirtual(Class<?> refc, String name, MethodType type) throws NoSuchMethodException, IllegalAccessException {
              if (refc == MethodHandle.class) {
                  MethodHandle mh = findVirtualForMH(name, type);
                  if (mh != null)  return mh;
              }
              byte refKind = (refc.isInterface() ? REF_invokeInterface : REF_invokeVirtual);
              MemberName method = resolveOrFail(refKind, refc, name, type);
              checkSecurityManager(refc, method);
              return getDirectMethod(refKind, refc, method, findBoundCallerClass(method));
          }
          private MethodHandle findVirtualForMH(String name, MethodType type) {
              // these names require special lookups because of the implicit MethodType argument
              if ("invoke".equals(name))
                  return invoker(type);
              if ("invokeExact".equals(name))
                  return exactInvoker(type);
              return null;
          }
  
          /**
           * Produces a method handle which creates an object and initializes it, using
           * the constructor of the specified type.
           * The parameter types of the method handle will be those of the constructor,
           * while the return type will be a reference to the constructor's class.
           * The constructor and all its argument types must be accessible to the lookup class.
           * If the constructor's class has not yet been initialized, that is done
           * immediately, before the method handle is returned.
           * <p>
           * Note:  The requested type must have a return type of {@code void}.
           * This is consistent with the JVM's treatment of constructor type descriptors.
           * <p>
           * The returned method handle will have
           * {@linkplain MethodHandle#asVarargsCollector variable arity} if and only if
           * the constructor's variable arity modifier bit ({@code 0x0080}) is set.
           * @param refc the class or interface from which the method is accessed
           * @param type the type of the method, with the receiver argument omitted, and a void return type
           * @return the desired method handle
           * @throws NoSuchMethodException if the constructor does not exist
           * @throws IllegalAccessException if access checking fails
           *                                or if the method's variable arity modifier bit
           *                                is set and {@code asVarargsCollector} fails
           * @exception SecurityException if a security manager is present and it
           *                              <a href="MethodHandles.Lookup.html#secmgr">refuses access</a>
           * @throws NullPointerException if any argument is null
           */
          public MethodHandle findConstructor(Class<?> refc, MethodType type) throws NoSuchMethodException, IllegalAccessException {
              String name = "<init>";
              MemberName ctor = resolveOrFail(REF_newInvokeSpecial, refc, name, type);
              checkSecurityManager(refc, ctor);
              return getDirectConstructor(refc, ctor);
          }
  
          /**
           * Produces an early-bound method handle for a virtual method,
           * as if called from an {@code invokespecial}
           * instruction from {@code caller}.
           * The type of the method handle will be that of the method,
           * with a suitably restricted receiver type (such as {@code caller}) prepended.
           * The method and all its argument types must be accessible
           * to the caller.
           * <p>
           * When called, the handle will treat the first argument as a receiver,
           * but will not dispatch on the receiver's type.
           * (This direct invocation action is identical with that performed by an
           * {@code invokespecial} instruction.)
           * <p>
           * If the explicitly specified caller class is not identical with the
           * lookup class, or if this lookup object does not have private access
           * privileges, the access fails.
           * <p>
           * The returned method handle will have
           * {@linkplain MethodHandle#asVarargsCollector variable arity} if and only if
           * the method's variable arity modifier bit ({@code 0x0080}) is set.
           * @param refc the class or interface from which the method is accessed
           * @param name the name of the method (which must not be "&lt;init&gt;")
           * @param type the type of the method, with the receiver argument omitted
           * @param specialCaller the proposed calling class to perform the {@code invokespecial}
           * @return the desired method handle
           * @throws NoSuchMethodException if the method does not exist
           * @throws IllegalAccessException if access checking fails
           *                                or if the method's variable arity modifier bit
           *                                is set and {@code asVarargsCollector} fails
           * @exception SecurityException if a security manager is present and it
           *                              <a href="MethodHandles.Lookup.html#secmgr">refuses access</a>
           * @throws NullPointerException if any argument is null
           */
          public MethodHandle findSpecial(Class<?> refc, String name, MethodType type,
                                          Class<?> specialCaller) throws NoSuchMethodException, IllegalAccessException {
              checkSpecialCaller(specialCaller);
              Lookup specialLookup = this.in(specialCaller);
              MemberName method = specialLookup.resolveOrFail(REF_invokeSpecial, refc, name, type);
              checkSecurityManager(refc, method);
              return specialLookup.getDirectMethod(REF_invokeSpecial, refc, method, findBoundCallerClass(method));
          }
  
          /**
           * Produces a method handle giving read access to a non-static field.
           * The type of the method handle will have a return type of the field's
           * value type.
           * The method handle's single argument will be the instance containing
           * the field.
           * Access checking is performed immediately on behalf of the lookup class.
           * @param refc the class or interface from which the method is accessed
           * @param name the field's name
           * @param type the field's type
           * @return a method handle which can load values from the field
           * @throws NoSuchFieldException if the field does not exist
           * @throws IllegalAccessException if access checking fails, or if the field is {@code static}
           * @exception SecurityException if a security manager is present and it
           *                              <a href="MethodHandles.Lookup.html#secmgr">refuses access</a>
           * @throws NullPointerException if any argument is null
           */
          public MethodHandle findGetter(Class<?> refc, String name, Class<?> type) throws NoSuchFieldException, IllegalAccessException {
              MemberName field = resolveOrFail(REF_getField, refc, name, type);
              checkSecurityManager(refc, field);
              return getDirectField(REF_getField, refc, field);
          }
  
          /**
           * Produces a method handle giving write access to a non-static field.
           * The type of the method handle will have a void return type.
           * The method handle will take two arguments, the instance containing
           * the field, and the value to be stored.
           * The second argument will be of the field's value type.
           * Access checking is performed immediately on behalf of the lookup class.
           * @param refc the class or interface from which the method is accessed
           * @param name the field's name
           * @param type the field's type
           * @return a method handle which can store values into the field
           * @throws NoSuchFieldException if the field does not exist
           * @throws IllegalAccessException if access checking fails, or if the field is {@code static}
           * @exception SecurityException if a security manager is present and it
           *                              <a href="MethodHandles.Lookup.html#secmgr">refuses access</a>
           * @throws NullPointerException if any argument is null
           */
          public MethodHandle findSetter(Class<?> refc, String name, Class<?> type) throws NoSuchFieldException, IllegalAccessException {
              MemberName field = resolveOrFail(REF_putField, refc, name, type);
              checkSecurityManager(refc, field);
              return getDirectField(REF_putField, refc, field);
          }
  
          /**
           * Produces a method handle giving read access to a static field.
           * The type of the method handle will have a return type of the field's
           * value type.
           * The method handle will take no arguments.
           * Access checking is performed immediately on behalf of the lookup class.
           * @param refc the class or interface from which the method is accessed
           * @param name the field's name
           * @param type the field's type
           * @return a method handle which can load values from the field
           * @throws NoSuchFieldException if the field does not exist
           * @throws IllegalAccessException if access checking fails, or if the field is not {@code static}
           * @exception SecurityException if a security manager is present and it
           *                              <a href="MethodHandles.Lookup.html#secmgr">refuses access</a>
           * @throws NullPointerException if any argument is null
           */
          public MethodHandle findStaticGetter(Class<?> refc, String name, Class<?> type) throws NoSuchFieldException, IllegalAccessException {
              MemberName field = resolveOrFail(REF_getStatic, refc, name, type);
              checkSecurityManager(refc, field);
              return getDirectField(REF_getStatic, refc, field);
          }
  
          /**
           * Produces a method handle giving write access to a static field.
           * The type of the method handle will have a void return type.
           * The method handle will take a single
           * argument, of the field's value type, the value to be stored.
           * Access checking is performed immediately on behalf of the lookup class.
           * @param refc the class or interface from which the method is accessed
           * @param name the field's name
           * @param type the field's type
           * @return a method handle which can store values into the field
           * @throws NoSuchFieldException if the field does not exist
           * @throws IllegalAccessException if access checking fails, or if the field is not {@code static}
           * @exception SecurityException if a security manager is present and it
           *                              <a href="MethodHandles.Lookup.html#secmgr">refuses access</a>
           * @throws NullPointerException if any argument is null
           */
          public MethodHandle findStaticSetter(Class<?> refc, String name, Class<?> type) throws NoSuchFieldException, IllegalAccessException {
              MemberName field = resolveOrFail(REF_putStatic, refc, name, type);
              checkSecurityManager(refc, field);
              return getDirectField(REF_putStatic, refc, field);
          }
  
          /**
           * Produces an early-bound method handle for a non-static method.
           * The receiver must have a supertype {@code defc} in which a method
           * of the given name and type is accessible to the lookup class.
           * The method and all its argument types must be accessible to the lookup class.
           * The type of the method handle will be that of the method,
           * without any insertion of an additional receiver parameter.
           * The given receiver will be bound into the method handle,
           * so that every call to the method handle will invoke the
           * requested method on the given receiver.
           * <p>
           * The returned method handle will have
           * {@linkplain MethodHandle#asVarargsCollector variable arity} if and only if
           * the method's variable arity modifier bit ({@code 0x0080}) is set
           * <em>and</em> the trailing array argument is not the only argument.
           * (If the trailing array argument is the only argument,
           * the given receiver value will be bound to it.)
           * <p>
           * This is equivalent to the following code:
           * <blockquote><pre>
  import static java.lang.invoke.MethodHandles.*;
  import static java.lang.invoke.MethodType.*;
  ...
  MethodHandle mh0 = lookup().{@link #findVirtual findVirtual}(defc, name, type);
  MethodHandle mh1 = mh0.{@link MethodHandle#bindTo bindTo}(receiver);
  MethodType mt1 = mh1.type();
  if (mh0.isVarargsCollector())
    mh1 = mh1.asVarargsCollector(mt1.parameterType(mt1.parameterCount()-1));
  return mh1;
           * </pre></blockquote>
           * where {@code defc} is either {@code receiver.getClass()} or a super
           * type of that class, in which the requested method is accessible
           * to the lookup class.
           * (Note that {@code bindTo} does not preserve variable arity.)
           * @param receiver the object from which the method is accessed
           * @param name the name of the method
           * @param type the type of the method, with the receiver argument omitted
           * @return the desired method handle
           * @throws NoSuchMethodException if the method does not exist
           * @throws IllegalAccessException if access checking fails
           *                                or if the method's variable arity modifier bit
           *                                is set and {@code asVarargsCollector} fails
           * @exception SecurityException if a security manager is present and it
           *                              <a href="MethodHandles.Lookup.html#secmgr">refuses access</a>
           * @throws NullPointerException if any argument is null
           */
          public MethodHandle bind(Object receiver, String name, MethodType type) throws NoSuchMethodException, IllegalAccessException {
              Class<? extends Object> refc = receiver.getClass(); // may get NPE
              MemberName method = resolveOrFail(REF_invokeSpecial, refc, name, type);
              checkSecurityManager(refc, method);
              MethodHandle mh = getDirectMethodNoRestrict(REF_invokeSpecial, refc, method, findBoundCallerClass(method));
              return mh.bindReceiver(receiver).setVarargs(method);
          }
  
          /**
           * Makes a direct method handle to <i>m</i>, if the lookup class has permission.
           * If <i>m</i> is non-static, the receiver argument is treated as an initial argument.
           * If <i>m</i> is virtual, overriding is respected on every call.
           * Unlike the Core Reflection API, exceptions are <em>not</em> wrapped.
           * The type of the method handle will be that of the method,
           * with the receiver type prepended (but only if it is non-static).
           * If the method's {@code accessible} flag is not set,
           * access checking is performed immediately on behalf of the lookup class.
           * If <i>m</i> is not public, do not share the resulting handle with untrusted parties.
           * <p>
           * The returned method handle will have
           * {@linkplain MethodHandle#asVarargsCollector variable arity} if and only if
           * the method's variable arity modifier bit ({@code 0x0080}) is set.
           * @param m the reflected method
           * @return a method handle which can invoke the reflected method
           * @throws IllegalAccessException if access checking fails
           *                                or if the method's variable arity modifier bit
           *                                is set and {@code asVarargsCollector} fails
           * @throws NullPointerException if the argument is null
           */
          public MethodHandle unreflect(Method m) throws IllegalAccessException {
              MemberName method = new MemberName(m);
              byte refKind = method.getReferenceKind();
              if (refKind == REF_invokeSpecial)
                  refKind = REF_invokeVirtual;
              assert(method.isMethod());
              Lookup lookup = m.isAccessible() ? IMPL_LOOKUP : this;
              return lookup.getDirectMethod(refKind, method.getDeclaringClass(), method, findBoundCallerClass(method));
          }
  
          /**
           * Produces a method handle for a reflected method.
           * It will bypass checks for overriding methods on the receiver,
           * as if by a {@code invokespecial} instruction from within the {@code specialCaller}.
           * The type of the method handle will be that of the method,
           * with the special caller type prepended (and <em>not</em> the receiver of the method).
           * If the method's {@code accessible} flag is not set,
           * access checking is performed immediately on behalf of the lookup class,
           * as if {@code invokespecial} instruction were being linked.
           * <p>
           * The returned method handle will have
           * {@linkplain MethodHandle#asVarargsCollector variable arity} if and only if
           * the method's variable arity modifier bit ({@code 0x0080}) is set.
           * @param m the reflected method
           * @param specialCaller the class nominally calling the method
           * @return a method handle which can invoke the reflected method
           * @throws IllegalAccessException if access checking fails
           *                                or if the method's variable arity modifier bit
           *                                is set and {@code asVarargsCollector} fails
           * @throws NullPointerException if any argument is null
           */
          public MethodHandle unreflectSpecial(Method m, Class<?> specialCaller) throws IllegalAccessException {
              checkSpecialCaller(specialCaller);
              Lookup specialLookup = this.in(specialCaller);
              MemberName method = new MemberName(m, true);
              assert(method.isMethod());
              // ignore m.isAccessible:  this is a new kind of access
              return specialLookup.getDirectMethod(REF_invokeSpecial, method.getDeclaringClass(), method, findBoundCallerClass(method));
          }
  
          /**
           * Produces a method handle for a reflected constructor.
           * The type of the method handle will be that of the constructor,
           * with the return type changed to the declaring class.
           * The method handle will perform a {@code newInstance} operation,
           * creating a new instance of the constructor's class on the
           * arguments passed to the method handle.
           * <p>
           * If the constructor's {@code accessible} flag is not set,
           * access checking is performed immediately on behalf of the lookup class.
           * <p>
           * The returned method handle will have
           * {@linkplain MethodHandle#asVarargsCollector variable arity} if and only if
           * the constructor's variable arity modifier bit ({@code 0x0080}) is set.
           * @param c the reflected constructor
           * @return a method handle which can invoke the reflected constructor
           * @throws IllegalAccessException if access checking fails
           *                                or if the method's variable arity modifier bit
           *                                is set and {@code asVarargsCollector} fails
           * @throws NullPointerException if the argument is null
           */
          @SuppressWarnings("rawtypes")  // Will be Constructor<?> after JSR 292 MR
          public MethodHandle unreflectConstructor(Constructor c) throws IllegalAccessException {
              MemberName ctor = new MemberName(c);
              assert(ctor.isConstructor());
              Lookup lookup = c.isAccessible() ? IMPL_LOOKUP : this;
              return lookup.getDirectConstructor(ctor.getDeclaringClass(), ctor);
          }
  
          /**
           * Produces a method handle giving read access to a reflected field.
           * The type of the method handle will have a return type of the field's
           * value type.
           * If the field is static, the method handle will take no arguments.
           * Otherwise, its single argument will be the instance containing
           * the field.
           * If the field's {@code accessible} flag is not set,
           * access checking is performed immediately on behalf of the lookup class.
           * @param f the reflected field
           * @return a method handle which can load values from the reflected field
           * @throws IllegalAccessException if access checking fails
           * @throws NullPointerException if the argument is null
           */
          public MethodHandle unreflectGetter(Field f) throws IllegalAccessException {
              return unreflectField(f, false);
          }
          private MethodHandle unreflectField(Field f, boolean isSetter) throws IllegalAccessException {
              MemberName field = new MemberName(f, isSetter);
              assert(isSetter
                      ? MethodHandleNatives.refKindIsSetter(field.getReferenceKind())
                      : MethodHandleNatives.refKindIsGetter(field.getReferenceKind()));
              Lookup lookup = f.isAccessible() ? IMPL_LOOKUP : this;
              return lookup.getDirectField(field.getReferenceKind(), f.getDeclaringClass(), field);
          }
  
          /**
           * Produces a method handle giving write access to a reflected field.
           * The type of the method handle will have a void return type.
           * If the field is static, the method handle will take a single
           * argument, of the field's value type, the value to be stored.
           * Otherwise, the two arguments will be the instance containing
           * the field, and the value to be stored.
           * If the field's {@code accessible} flag is not set,
           * access checking is performed immediately on behalf of the lookup class.
           * @param f the reflected field
           * @return a method handle which can store values into the reflected field
           * @throws IllegalAccessException if access checking fails
           * @throws NullPointerException if the argument is null
           */
          public MethodHandle unreflectSetter(Field f) throws IllegalAccessException {
              return unreflectField(f, true);
          }
  
          /// Helper methods, all package-private.
  
          MemberName resolveOrFail(byte refKind, Class<?> refc, String name, Class<?> type) throws NoSuchFieldException, IllegalAccessException {
              checkSymbolicClass(refc);  // do this before attempting to resolve
              name.getClass(); type.getClass();  // NPE
              return IMPL_NAMES.resolveOrFail(refKind, new MemberName(refc, name, type, refKind), lookupClassOrNull(),
                                              NoSuchFieldException.class);
          }
  
          MemberName resolveOrFail(byte refKind, Class<?> refc, String name, MethodType type) throws NoSuchMethodException, IllegalAccessException {
              checkSymbolicClass(refc);  // do this before attempting to resolve
              name.getClass(); type.getClass();  // NPE
              return IMPL_NAMES.resolveOrFail(refKind, new MemberName(refc, name, type, refKind), lookupClassOrNull(),
                                              NoSuchMethodException.class);
          }
  
          void checkSymbolicClass(Class<?> refc) throws IllegalAccessException {
              Class<?> caller = lookupClassOrNull();
              if (caller != null && !VerifyAccess.isClassAccessible(refc, caller, allowedModes))
                  throw new MemberName(refc).makeAccessException("symbolic reference class is not public", this);
          }
  
          /**
           * Find my trustable caller class if m is a caller sensitive method.
           * If this lookup object has private access, then the caller class is the lookupClass.
           * Otherwise, if m is caller-sensitive, throw IllegalAccessException.
           */
          Class<?> findBoundCallerClass(MemberName m) throws IllegalAccessException {
              Class<?> callerClass = null;
              if (MethodHandleNatives.isCallerSensitive(m)) {
                  // Only full-power lookup is allowed to resolve caller-sensitive methods
                  if (isFullPowerLookup()) {
                      callerClass = lookupClass;
                  } else {
                      throw new IllegalAccessException("Attempt to lookup caller-sensitive method using restricted lookup object");
                  }
              }
              return callerClass;
          }
  
          private boolean isFullPowerLookup() {
              return (allowedModes & PRIVATE) != 0;
          }
  
          /**
           * Determine whether a security manager has an overridden
           * SecurityManager.checkMemberAccess method.
           */
          private boolean isCheckMemberAccessOverridden(SecurityManager sm) {
              final Class<? extends SecurityManager> cls = sm.getClass();
              if (cls == SecurityManager.class) return false;
  
              try {
                  return cls.getMethod("checkMemberAccess", Class.class, int.class).
                      getDeclaringClass() != SecurityManager.class;
              } catch (NoSuchMethodException e) {
                  throw new InternalError("should not reach here");
              }
          }
  
          /**
           * Perform necessary <a href="MethodHandles.Lookup.html#secmgr">access checks</a>.
           * This function performs stack walk magic: do not refactor it.
           */
          void checkSecurityManager(Class<?> refc, MemberName m) {
              SecurityManager smgr = System.getSecurityManager();
              if (smgr == null)  return;
              if (allowedModes == TRUSTED)  return;
  
              final boolean overridden = isCheckMemberAccessOverridden(smgr);
              // Step 1:
              {
                  // Default policy is to allow Member.PUBLIC; no need to check
                  // permission if SecurityManager is the default implementation
                  final int which = Member.PUBLIC;
                  final Class<?> clazz = refc;
                  if (overridden) {
                      // Don't refactor; otherwise break the stack depth for
                      // checkMemberAccess of subclasses of SecurityManager as specified.
                      smgr.checkMemberAccess(clazz, which);
                  }
              }
  
              // Step 2:
              if (!isFullPowerLookup() ||
                  !VerifyAccess.classLoaderIsAncestor(lookupClass, refc)) {
                  ReflectUtil.checkPackageAccess(refc);
              }
  
              // Step 3:
              if (m.isPublic()) return;
              Class<?> defc = m.getDeclaringClass();
              {
                  // Inline SecurityManager.checkMemberAccess
                  final int which = Member.DECLARED;
                  final Class<?> clazz = defc;
                  if (!overridden) {
                      if (!isFullPowerLookup()) {
                          smgr.checkPermission(SecurityConstants.CHECK_MEMBER_ACCESS_PERMISSION);
                      }
                  } else {
                      // Don't refactor; otherwise break the stack depth for
                      // checkMemberAccess of subclasses of SecurityManager as specified.
                      smgr.checkMemberAccess(clazz, which);
                  }
              }
  
              // Step 4:
              if (defc != refc) {
                  ReflectUtil.checkPackageAccess(defc);
              }
          }
  
          void checkMethod(byte refKind, Class<?> refc, MemberName m) throws IllegalAccessException {
              boolean wantStatic = (refKind == REF_invokeStatic);
              String message;
              if (m.isConstructor())
                  message = "expected a method, not a constructor";
              else if (!m.isMethod())
                  message = "expected a method";
              else if (wantStatic != m.isStatic())
                  message = wantStatic ? "expected a static method" : "expected a non-static method";
              else
                  { checkAccess(refKind, refc, m); return; }
              throw m.makeAccessException(message, this);
          }
  
          void checkField(byte refKind, Class<?> refc, MemberName m) throws IllegalAccessException {
              boolean wantStatic = !MethodHandleNatives.refKindHasReceiver(refKind);
              String message;
              if (wantStatic != m.isStatic())
                  message = wantStatic ? "expected a static field" : "expected a non-static field";
              else
                  { checkAccess(refKind, refc, m); return; }
              throw m.makeAccessException(message, this);
          }
  
          void checkAccess(byte refKind, Class<?> refc, MemberName m) throws IllegalAccessException {
              assert(m.referenceKindIsConsistentWith(refKind) &&
                     MethodHandleNatives.refKindIsValid(refKind) &&
                     (MethodHandleNatives.refKindIsField(refKind) == m.isField()));
              int allowedModes = this.allowedModes;
              if (allowedModes == TRUSTED)  return;
              int mods = m.getModifiers();
              if (Modifier.isFinal(mods) &&
                      MethodHandleNatives.refKindIsSetter(refKind))
                  throw m.makeAccessException("unexpected set of a final field", this);
              if (Modifier.isPublic(mods) && Modifier.isPublic(refc.getModifiers()) && allowedModes != 0)
                  return;  // common case
              int requestedModes = fixmods(mods);  // adjust 0 => PACKAGE
              if ((requestedModes & allowedModes) != 0) {
                  if (VerifyAccess.isMemberAccessible(refc, m.getDeclaringClass(),
                                                      mods, lookupClass(), allowedModes))
                      return;
              } else {
                  // Protected members can also be checked as if they were package-private.
                  if ((requestedModes & PROTECTED) != 0 && (allowedModes & PACKAGE) != 0
                          && VerifyAccess.isSamePackage(m.getDeclaringClass(), lookupClass()))
                      return;
              }
              throw m.makeAccessException(accessFailedMessage(refc, m), this);
          }
  
          String accessFailedMessage(Class<?> refc, MemberName m) {
              Class<?> defc = m.getDeclaringClass();
              int mods = m.getModifiers();
              // check the class first:
              boolean classOK = (Modifier.isPublic(defc.getModifiers()) &&
                                 (defc == refc ||
                                  Modifier.isPublic(refc.getModifiers())));
              if (!classOK && (allowedModes & PACKAGE) != 0) {
                  classOK = (VerifyAccess.isClassAccessible(defc, lookupClass(), ALL_MODES) &&
                             (defc == refc ||
                              VerifyAccess.isClassAccessible(refc, lookupClass(), ALL_MODES)));
              }
              if (!classOK)
                  return "class is not public";
              if (Modifier.isPublic(mods))
                  return "access to public member failed";  // (how?)
              if (Modifier.isPrivate(mods))
                  return "member is private";
              if (Modifier.isProtected(mods))
                  return "member is protected";
              return "member is private to package";
          }
  
          private static final boolean ALLOW_NESTMATE_ACCESS = false;
  
          private void checkSpecialCaller(Class<?> specialCaller) throws IllegalAccessException {
              int allowedModes = this.allowedModes;
              if (allowedModes == TRUSTED)  return;
              if ((allowedModes & PRIVATE) == 0
                  || (specialCaller != lookupClass()
                      && !(ALLOW_NESTMATE_ACCESS &&
                           VerifyAccess.isSamePackageMember(specialCaller, lookupClass()))))
                  throw new MemberName(specialCaller).
                      makeAccessException("no private access for invokespecial", this);
          }
  
          private boolean restrictProtectedReceiver(MemberName method) {
              // The accessing class only has the right to use a protected member
              // on itself or a subclass.  Enforce that restriction, from JVMS 5.4.4, etc.
              if (!method.isProtected() || method.isStatic()
                  || allowedModes == TRUSTED
                  || method.getDeclaringClass() == lookupClass()
                  || VerifyAccess.isSamePackage(method.getDeclaringClass(), lookupClass())
                  || (ALLOW_NESTMATE_ACCESS &&
                      VerifyAccess.isSamePackageMember(method.getDeclaringClass(), lookupClass())))
                  return false;
              return true;
          }
          private MethodHandle restrictReceiver(MemberName method, MethodHandle mh, Class<?> caller) throws IllegalAccessException {
              assert(!method.isStatic());
              // receiver type of mh is too wide; narrow to caller
              if (!method.getDeclaringClass().isAssignableFrom(caller)) {
                  throw method.makeAccessException("caller class must be a subclass below the method", caller);
              }
              MethodType rawType = mh.type();
              if (rawType.parameterType(0) == caller)  return mh;
              MethodType narrowType = rawType.changeParameterType(0, caller);
              return mh.viewAsType(narrowType);
          }
  
          private MethodHandle getDirectMethod(byte refKind, Class<?> refc, MemberName method, Class<?> callerClass) throws IllegalAccessException {
              return getDirectMethodCommon(refKind, refc, method,
                      (refKind == REF_invokeSpecial ||
                          (MethodHandleNatives.refKindHasReceiver(refKind) &&
                              restrictProtectedReceiver(method))), callerClass);
          }
          private MethodHandle getDirectMethodNoRestrict(byte refKind, Class<?> refc, MemberName method, Class<?> callerClass) throws IllegalAccessException {
              return getDirectMethodCommon(refKind, refc, method, false, callerClass);
          }
          private MethodHandle getDirectMethodCommon(byte refKind, Class<?> refc, MemberName method,
                                                     boolean doRestrict, Class<?> callerClass) throws IllegalAccessException {
              checkMethod(refKind, refc, method);
              if (method.isMethodHandleInvoke())
                  return fakeMethodHandleInvoke(method);
  
              Class<?> refcAsSuper;
              if (refKind == REF_invokeSpecial &&
                  refc != lookupClass() &&
                  refc != (refcAsSuper = lookupClass().getSuperclass()) &&
                  refc.isAssignableFrom(lookupClass())) {
                  assert(!method.getName().equals("<init>"));  // not this code path
                  // Per JVMS 6.5, desc. of invokespecial instruction:
                  // If the method is in a superclass of the LC,
                  // and if our original search was above LC.super,
                  // repeat the search (symbolic lookup) from LC.super.
                  // FIXME: MemberName.resolve should handle this instead.
                  MemberName m2 = new MemberName(refcAsSuper,
                                                 method.getName(),
                                                 method.getMethodType(),
                                                 REF_invokeSpecial);
                  m2 = IMPL_NAMES.resolveOrNull(refKind, m2, lookupClassOrNull());
                  if (m2 == null)  throw new InternalError(method.toString());
                  method = m2;
                  refc = refcAsSuper;
                  // redo basic checks
                  checkMethod(refKind, refc, method);
              }
  
              MethodHandle mh = DirectMethodHandle.make(refc, method);
              mh = maybeBindCaller(method, mh, callerClass);
              mh = mh.setVarargs(method);
              if (doRestrict)
                  mh = restrictReceiver(method, mh, lookupClass());
              return mh;
          }
          private MethodHandle fakeMethodHandleInvoke(MemberName method) {
              return throwException(method.getReturnType(), UnsupportedOperationException.class);
          }
          private MethodHandle maybeBindCaller(MemberName method, MethodHandle mh,
                                               Class<?> callerClass)
                                               throws IllegalAccessException {
              if (allowedModes == TRUSTED || !MethodHandleNatives.isCallerSensitive(method))
                  return mh;
              Class<?> hostClass = lookupClass;
              if ((allowedModes & PRIVATE) == 0)  // caller must use full-power lookup
                  hostClass = callerClass;  // callerClass came from a security manager style stack walk
              MethodHandle cbmh = MethodHandleImpl.bindCaller(mh, hostClass);
              // Note: caller will apply varargs after this step happens.
              return cbmh;
          }
          private MethodHandle getDirectField(byte refKind, Class<?> refc, MemberName field) throws IllegalAccessException {
              checkField(refKind, refc, field);
              MethodHandle mh = DirectMethodHandle.make(refc, field);
              boolean doRestrict = (MethodHandleNatives.refKindHasReceiver(refKind) &&
                                      restrictProtectedReceiver(field));
              if (doRestrict)
                  mh = restrictReceiver(field, mh, lookupClass());
              return mh;
          }
          private MethodHandle getDirectConstructor(Class<?> refc, MemberName ctor) throws IllegalAccessException {
              assert(ctor.isConstructor());
              checkAccess(REF_newInvokeSpecial, refc, ctor);
              assert(!MethodHandleNatives.isCallerSensitive(ctor));  // maybeBindCaller not relevant here
              return DirectMethodHandle.make(ctor).setVarargs(ctor);
          }
  
          /** Hook called from the JVM (via MethodHandleNatives) to link MH constants:
           */
          /*non-public*/
          MethodHandle linkMethodHandleConstant(byte refKind, Class<?> defc, String name, Object type) throws ReflectiveOperationException {
              MemberName resolved = null;
              if (type instanceof MemberName) {
                  resolved = (MemberName) type;
                  if (!resolved.isResolved())  throw new InternalError("unresolved MemberName");
                  assert(name == null || name.equals(resolved.getName()));
              }
              if (MethodHandleNatives.refKindIsField(refKind)) {
                  MemberName field = (resolved != null) ? resolved
                          : resolveOrFail(refKind, defc, name, (Class<?>) type);
                  return getDirectField(refKind, defc, field);
              } else if (MethodHandleNatives.refKindIsMethod(refKind)) {
                  if (defc == MethodHandle.class && refKind == REF_invokeVirtual) {
                      MethodHandle mh = findVirtualForMH(name, (MethodType) type);
                      if (mh != null)  return mh;
                  }
                  MemberName method = (resolved != null) ? resolved
                          : resolveOrFail(refKind, defc, name, (MethodType) type);
                  return getDirectMethod(refKind, defc, method, lookupClass);
              } else if (refKind == REF_newInvokeSpecial) {
                  assert(name == null || name.equals("<init>"));
                  MemberName ctor = (resolved != null) ? resolved
                          : resolveOrFail(REF_newInvokeSpecial, defc, name, (MethodType) type);
                  return getDirectConstructor(defc, ctor);
              }
              // oops
              throw new ReflectiveOperationException("bad MethodHandle constant #"+refKind+" "+name+" : "+type);
          }
      }
  
      /**
       * Produces a method handle giving read access to elements of an array.
       * The type of the method handle will have a return type of the array's
       * element type.  Its first argument will be the array type,
       * and the second will be {@code int}.
       * @param arrayClass an array type
       * @return a method handle which can load values from the given array type
       * @throws NullPointerException if the argument is null
       * @throws  IllegalArgumentException if arrayClass is not an array type
       */
      public static
      MethodHandle arrayElementGetter(Class<?> arrayClass) throws IllegalArgumentException {
          return MethodHandleImpl.makeArrayElementAccessor(arrayClass, false);
      }
  
      /**
       * Produces a method handle giving write access to elements of an array.
       * The type of the method handle will have a void return type.
       * Its last argument will be the array's element type.
       * The first and second arguments will be the array type and int.
       * @return a method handle which can store values into the array type
       * @throws NullPointerException if the argument is null
       * @throws IllegalArgumentException if arrayClass is not an array type
       */
      public static
      MethodHandle arrayElementSetter(Class<?> arrayClass) throws IllegalArgumentException {
          return MethodHandleImpl.makeArrayElementAccessor(arrayClass, true);
      }
  
      /// method handle invocation (reflective style)
  
      /**
       * Produces a method handle which will invoke any method handle of the
       * given {@code type}, with a given number of trailing arguments replaced by
       * a single trailing {@code Object[]} array.
       * The resulting invoker will be a method handle with the following
       * arguments:
       * <ul>
       * <li>a single {@code MethodHandle} target
       * <li>zero or more leading values (counted by {@code leadingArgCount})
       * <li>an {@code Object[]} array containing trailing arguments
       * </ul>
       * <p>
       * The invoker will invoke its target like a call to {@link MethodHandle#invoke invoke} with
       * the indicated {@code type}.
       * That is, if the target is exactly of the given {@code type}, it will behave
       * like {@code invokeExact}; otherwise it behave as if {@link MethodHandle#asType asType}
       * is used to convert the target to the required {@code type}.
       * <p>
       * The type of the returned invoker will not be the given {@code type}, but rather
       * will have all parameters except the first {@code leadingArgCount}
       * replaced by a single array of type {@code Object[]}, which will be
       * the final parameter.
       * <p>
       * Before invoking its target, the invoker will spread the final array, apply
       * reference casts as necessary, and unbox and widen primitive arguments.
       * <p>
       * This method is equivalent to the following code (though it may be more efficient):
       * <p><blockquote><pre>
  MethodHandle invoker = MethodHandles.invoker(type);
  int spreadArgCount = type.parameterCount() - leadingArgCount;
  invoker = invoker.asSpreader(Object[].class, spreadArgCount);
  return invoker;
       * </pre></blockquote>
       * <p>
       * This method throws no reflective or security exceptions.
       * @param type the desired target type
       * @param leadingArgCount number of fixed arguments, to be passed unchanged to the target
       * @return a method handle suitable for invoking any method handle of the given type
       * @throws NullPointerException if {@code type} is null
       * @throws IllegalArgumentException if {@code leadingArgCount} is not in
       *                  the range from 0 to {@code type.parameterCount()} inclusive
       */
      static public
      MethodHandle spreadInvoker(MethodType type, int leadingArgCount) {
          if (leadingArgCount < 0 || leadingArgCount > type.parameterCount())
              throw new IllegalArgumentException("bad argument count "+leadingArgCount);
          return type.invokers().spreadInvoker(leadingArgCount);
      }
  
      /**
       * Produces a special <em>invoker method handle</em> which can be used to
       * invoke any method handle of the given type, as if by {@link MethodHandle#invokeExact invokeExact}.
       * The resulting invoker will have a type which is
       * exactly equal to the desired type, except that it will accept
       * an additional leading argument of type {@code MethodHandle}.
       * <p>
       * This method is equivalent to the following code (though it may be more efficient):
       * <p><blockquote><pre>
  publicLookup().findVirtual(MethodHandle.class, "invokeExact", type)
       * </pre></blockquote>
       *
       * <p style="font-size:smaller;">
       * <em>Discussion:</em>
       * Invoker method handles can be useful when working with variable method handles
       * of unknown types.
       * For example, to emulate an {@code invokeExact} call to a variable method
       * handle {@code M}, extract its type {@code T},
       * look up the invoker method {@code X} for {@code T},
       * and call the invoker method, as {@code X.invoke(T, A...)}.
       * (It would not work to call {@code X.invokeExact}, since the type {@code T}
       * is unknown.)
       * If spreading, collecting, or other argument transformations are required,
       * they can be applied once to the invoker {@code X} and reused on many {@code M}
       * method handle values, as long as they are compatible with the type of {@code X}.
       * <p>
       * <em>(Note:  The invoker method is not available via the Core Reflection API.
       * An attempt to call {@linkplain java.lang.reflect.Method#invoke java.lang.reflect.Method.invoke}
       * on the declared {@code invokeExact} or {@code invoke} method will raise an
       * {@link java.lang.UnsupportedOperationException UnsupportedOperationException}.)</em>
       * <p>
       * This method throws no reflective or security exceptions.
       * @param type the desired target type
       * @return a method handle suitable for invoking any method handle of the given type
       */
      static public
      MethodHandle exactInvoker(MethodType type) {
          return type.invokers().exactInvoker();
      }
  
      /**
       * Produces a special <em>invoker method handle</em> which can be used to
       * invoke any method handle compatible with the given type, as if by {@link MethodHandle#invoke invoke}.
       * The resulting invoker will have a type which is
       * exactly equal to the desired type, except that it will accept
       * an additional leading argument of type {@code MethodHandle}.
       * <p>
       * Before invoking its target, if the target differs from the expected type,
       * the invoker will apply reference casts as
       * necessary and box, unbox, or widen primitive values, as if by {@link MethodHandle#asType asType}.
       * Similarly, the return value will be converted as necessary.
       * If the target is a {@linkplain MethodHandle#asVarargsCollector variable arity method handle},
       * the required arity conversion will be made, again as if by {@link MethodHandle#asType asType}.
       * <p>
       * A {@linkplain MethodType#genericMethodType general method type},
       * mentions only {@code Object} arguments and return values.
       * An invoker for such a type is capable of calling any method handle
       * of the same arity as the general type.
       * <p>
       * This method is equivalent to the following code (though it may be more efficient):
       * <p><blockquote><pre>
  publicLookup().findVirtual(MethodHandle.class, "invoke", type)
       * </pre></blockquote>
       * <p>
       * This method throws no reflective or security exceptions.
       * @param type the desired target type
       * @return a method handle suitable for invoking any method handle convertible to the given type
       */
      static public
      MethodHandle invoker(MethodType type) {
          return type.invokers().generalInvoker();
      }
  
      static /*non-public*/
      MethodHandle basicInvoker(MethodType type) {
          return type.form().basicInvoker();
      }
  
       /// method handle modification (creation from other method handles)
  
      /**
       * Produces a method handle which adapts the type of the
       * given method handle to a new type by pairwise argument and return type conversion.
       * The original type and new type must have the same number of arguments.
       * The resulting method handle is guaranteed to report a type
       * which is equal to the desired new type.
       * <p>
       * If the original type and new type are equal, returns target.
       * <p>
       * The same conversions are allowed as for {@link MethodHandle#asType MethodHandle.asType},
       * and some additional conversions are also applied if those conversions fail.
       * Given types <em>T0</em>, <em>T1</em>, one of the following conversions is applied
       * if possible, before or instead of any conversions done by {@code asType}:
       * <ul>
       * <li>If <em>T0</em> and <em>T1</em> are references, and <em>T1</em> is an interface type,
       *     then the value of type <em>T0</em> is passed as a <em>T1</em> without a cast.
       *     (This treatment of interfaces follows the usage of the bytecode verifier.)
       * <li>If <em>T0</em> is boolean and <em>T1</em> is another primitive,
       *     the boolean is converted to a byte value, 1 for true, 0 for false.
       *     (This treatment follows the usage of the bytecode verifier.)
       * <li>If <em>T1</em> is boolean and <em>T0</em> is another primitive,
       *     <em>T0</em> is converted to byte via Java casting conversion (JLS 5.5),
       *     and the low order bit of the result is tested, as if by {@code (x & 1) != 0}.
       * <li>If <em>T0</em> and <em>T1</em> are primitives other than boolean,
       *     then a Java casting conversion (JLS 5.5) is applied.
       *     (Specifically, <em>T0</em> will convert to <em>T1</em> by
       *     widening and/or narrowing.)
       * <li>If <em>T0</em> is a reference and <em>T1</em> a primitive, an unboxing
       *     conversion will be applied at runtime, possibly followed
       *     by a Java casting conversion (JLS 5.5) on the primitive value,
       *     possibly followed by a conversion from byte to boolean by testing
       *     the low-order bit.
       * <li>If <em>T0</em> is a reference and <em>T1</em> a primitive,
       *     and if the reference is null at runtime, a zero value is introduced.
       * </ul>
       * @param target the method handle to invoke after arguments are retyped
       * @param newType the expected type of the new method handle
       * @return a method handle which delegates to the target after performing
       *           any necessary argument conversions, and arranges for any
       *           necessary return value conversions
       * @throws NullPointerException if either argument is null
       * @throws WrongMethodTypeException if the conversion cannot be made
       * @see MethodHandle#asType
       */
      public static
      MethodHandle explicitCastArguments(MethodHandle target, MethodType newType) {
          if (!target.type().isCastableTo(newType)) {
              throw new WrongMethodTypeException("cannot explicitly cast "+target+" to "+newType);
          }
          return MethodHandleImpl.makePairwiseConvert(target, newType, 2);
      }
  
      /**
       * Produces a method handle which adapts the calling sequence of the
       * given method handle to a new type, by reordering the arguments.
       * The resulting method handle is guaranteed to report a type
       * which is equal to the desired new type.
       * <p>
       * The given array controls the reordering.
       * Call {@code #I} the number of incoming parameters (the value
       * {@code newType.parameterCount()}, and call {@code #O} the number
       * of outgoing parameters (the value {@code target.type().parameterCount()}).
       * Then the length of the reordering array must be {@code #O},
       * and each element must be a non-negative number less than {@code #I}.
       * For every {@code N} less than {@code #O}, the {@code N}-th
       * outgoing argument will be taken from the {@code I}-th incoming
       * argument, where {@code I} is {@code reorder[N]}.
       * <p>
       * No argument or return value conversions are applied.
       * The type of each incoming argument, as determined by {@code newType},
       * must be identical to the type of the corresponding outgoing parameter
       * or parameters in the target method handle.
       * The return type of {@code newType} must be identical to the return
       * type of the original target.
       * <p>
       * The reordering array need not specify an actual permutation.
       * An incoming argument will be duplicated if its index appears
       * more than once in the array, and an incoming argument will be dropped
       * if its index does not appear in the array.
       * As in the case of {@link #dropArguments(MethodHandle,int,List) dropArguments},
       * incoming arguments which are not mentioned in the reordering array
       * are may be any type, as determined only by {@code newType}.
       * <blockquote><pre>
  import static java.lang.invoke.MethodHandles.*;
  import static java.lang.invoke.MethodType.*;
  ...
  MethodType intfn1 = methodType(int.class, int.class);
  MethodType intfn2 = methodType(int.class, int.class, int.class);
  MethodHandle sub = ... {int x, int y => x-y} ...;
  assert(sub.type().equals(intfn2));
  MethodHandle sub1 = permuteArguments(sub, intfn2, 0, 1);
  MethodHandle rsub = permuteArguments(sub, intfn2, 1, 0);
  assert((int)rsub.invokeExact(1, 100) == 99);
  MethodHandle add = ... {int x, int y => x+y} ...;
  assert(add.type().equals(intfn2));
  MethodHandle twice = permuteArguments(add, intfn1, 0, 0);
  assert(twice.type().equals(intfn1));
  assert((int)twice.invokeExact(21) == 42);
       * </pre></blockquote>
       * @param target the method handle to invoke after arguments are reordered
       * @param newType the expected type of the new method handle
       * @param reorder an index array which controls the reordering
       * @return a method handle which delegates to the target after it
       *           drops unused arguments and moves and/or duplicates the other arguments
       * @throws NullPointerException if any argument is null
       * @throws IllegalArgumentException if the index array length is not equal to
       *                  the arity of the target, or if any index array element
       *                  not a valid index for a parameter of {@code newType},
       *                  or if two corresponding parameter types in
       *                  {@code target.type()} and {@code newType} are not identical,
       */
      public static
      MethodHandle permuteArguments(MethodHandle target, MethodType newType, int... reorder) {
          reorder = reorder.clone();
          checkReorder(reorder, newType, target.type());
          return target.permuteArguments(newType, reorder);
      }
  
      private static void checkReorder(int[] reorder, MethodType newType, MethodType oldType) {
          if (newType.returnType() != oldType.returnType())
              throw newIllegalArgumentException("return types do not match",
                      oldType, newType);
          if (reorder.length == oldType.parameterCount()) {
              int limit = newType.parameterCount();
              boolean bad = false;
              for (int j = 0; j < reorder.length; j++) {
                  int i = reorder[j];
                  if (i < 0 || i >= limit) {
                      bad = true; break;
                  }
                  Class<?> src = newType.parameterType(i);
                  Class<?> dst = oldType.parameterType(j);
                  if (src != dst)
                      throw newIllegalArgumentException("parameter types do not match after reorder",
                              oldType, newType);
              }
              if (!bad)  return;
          }
          throw newIllegalArgumentException("bad reorder array: "+Arrays.toString(reorder));
      }
  
      /**
       * Produces a method handle of the requested return type which returns the given
       * constant value every time it is invoked.
       * <p>
       * Before the method handle is returned, the passed-in value is converted to the requested type.
       * If the requested type is primitive, widening primitive conversions are attempted,
       * else reference conversions are attempted.
       * <p>The returned method handle is equivalent to {@code identity(type).bindTo(value)}.
       * @param type the return type of the desired method handle
       * @param value the value to return
       * @return a method handle of the given return type and no arguments, which always returns the given value
       * @throws NullPointerException if the {@code type} argument is null
       * @throws ClassCastException if the value cannot be converted to the required return type
       * @throws IllegalArgumentException if the given type is {@code void.class}
       */
      public static
      MethodHandle constant(Class<?> type, Object value) {
          if (type.isPrimitive()) {
              if (type == void.class)
                  throw newIllegalArgumentException("void type");
              Wrapper w = Wrapper.forPrimitiveType(type);
              return insertArguments(identity(type), 0, w.convert(value, type));
          } else {
              return identity(type).bindTo(type.cast(value));
          }
      }
  
      /**
       * Produces a method handle which returns its sole argument when invoked.
       * @param type the type of the sole parameter and return value of the desired method handle
       * @return a unary method handle which accepts and returns the given type
       * @throws NullPointerException if the argument is null
       * @throws IllegalArgumentException if the given type is {@code void.class}
       */
      public static
      MethodHandle identity(Class<?> type) {
          if (type == void.class)
  