title: GWT 2.6.1 unknown compile issue
body: <p>I know other people have had issues with GWT compiles, but in this case I am at a loss.
  I am using GWT 2.6.1  and the same version of the gwt-maven-plugin, 2.6.1</p>
  
  <p>First does GWT and/or SmartGWT support JDK 1.8 yet, or just 1.7 for now? I am using jdk 1.7, but would like to try 1.8 eventually.</p>
  
  <p>Second, when I do a maven build within eclipse I get this error ... 
  Yet, when I do a GWT compile from the GWT Eclipse Plugin, I right click on the project, and I tell it to GWT Compile and it does with no issues.</p>
  
  <pre><code>[INFO] --- gwt-maven-plugin:2.6.1:compile (default) @ rm-ui ---
  [INFO] auto discovered modules [com.redi2.products.rm.RevenueManager]
  [INFO] Compiling module com.redi2.products.rm.RevenueManager
  [INFO] [ERROR] Unexpected internal compiler error
  [INFO] java.lang.NoSuchFieldError: warningThreshold
  [INFO]  at com.google.gwt.dev.javac.JdtCompiler$1.&lt;init&gt;(JdtCompiler.java:505)
  [INFO]  at com.google.gwt.dev.javac.JdtCompiler.getStandardCompilerOptions(JdtCompiler.java:503)
  [INFO]  at com.google.gwt.dev.javac.JdtCompiler.getCompilerOptions(JdtCompiler.java:533)
  [INFO]  at com.google.gwt.dev.javac.JdtCompiler.doCompile(JdtCompiler.java:878)
  [INFO]  at com.google.gwt.dev.javac.CompilationStateBuilder$CompileMoreLater.compile(CompilationStateBuilder.java:284)
  [INFO]  at com.google.gwt.dev.javac.CompilationStateBuilder.doBuildFrom(CompilationStateBuilder.java:511)
  [INFO]  at com.google.gwt.dev.javac.CompilationStateBuilder.buildFrom(CompilationStateBuilder.java:434)
  [INFO]  at com.google.gwt.dev.javac.CompilationStateBuilder.buildFrom(CompilationStateBuilder.java:420)
  [INFO]  at com.google.gwt.dev.cfg.ModuleDef.getCompilationState(ModuleDef.java:495)
  [INFO]  at com.google.gwt.dev.Precompile.precompile(Precompile.java:241)
  [INFO]  at com.google.gwt.dev.Precompile.precompile(Precompile.java:223)
  [INFO]  at com.google.gwt.dev.Precompile.precompile(Precompile.java:139)
  [INFO]  at com.google.gwt.dev.Compiler.run(Compiler.java:167)
  [INFO]  at com.google.gwt.dev.Compiler.run(Compiler.java:132)
  [INFO]  at com.google.gwt.dev.Compiler$1.run(Compiler.java:99)
  [INFO]  at com.google.gwt.dev.CompileTaskRunner.doRun(CompileTaskRunner.java:55)
  [INFO]  at com.google.gwt.dev.CompileTaskRunner.runWithAppropriateLogger(CompileTaskRunner.java:50)
  [INFO]  at com.google.gwt.dev.Compiler.main(Compiler.java:106)
  </code></pre>
  
  <p>The next step was to go out of eclipse and try a mvn build from the command line, and that doesn't work.  So, I do the following:</p>
  
  <pre><code>mvn clean  - and that correctly deletes my target directory and the gwt-unitCache.
  mvn gwt:clean
  mvn -X -e gwt:compile --debug
  </code></pre>
  
  <p>At first, it was telling me that it couldn't find my:  com.tholmes.products.App.gwt.xml
  but I know it is there, I even deleted the file and re-added it.  It is very much part of the classpath, and it is there, and in the right format.</p>
  
  <p>so, I did a:</p>
  
  <pre><code>mvn gwt:eclipse  
  mvn gwt:eclipseTest
  </code></pre>
  
  <p>This seemed to fix the issue that it could not find the gwt.xml file.</p>
  
  <p>So, now I try again, and this is what I get with all the debug and stack trace.</p>
  
  <pre><code>[INFO] Compiling module com.redi2.products.rm.RevenueManager
  [INFO] [ERROR] Unexpected internal compiler error
  [INFO] java.lang.NoSuchFieldError: warningThreshold
  [INFO]  at com.google.gwt.dev.javac.JdtCompiler$1.&lt;init&gt;(JdtCompiler.java:505)
  [INFO]  at com.google.gwt.dev.javac.JdtCompiler.getStandardCompilerOptions(JdtCompiler.java:503)
  [INFO]  at com.google.gwt.dev.javac.JdtCompiler.getCompilerOptions(JdtCompiler.java:533)
  [INFO]  at com.google.gwt.dev.javac.JdtCompiler.doCompile(JdtCompiler.java:878)   
  [INFO]  at com.google.gwt.dev.javac.CompilationStateBuilder$CompileMoreLater.compile(CompilationStateBuilder.java:284)
  [INFO]  at com.google.gwt.dev.javac.CompilationStateBuilder.doBuildFrom(CompilationStateBuilder.java:511)
  [INFO]  at com.google.gwt.dev.javac.CompilationStateBuilder.buildFrom(CompilationStateBuilder.java:434)
  [INFO]  at com.google.gwt.dev.javac.CompilationStateBuilder.buildFrom(CompilationStateBuilder.java:420)
  [INFO]  at com.google.gwt.dev.cfg.ModuleDef.getCompilationState(ModuleDef.java:495)
  [INFO]  at com.google.gwt.dev.Precompile.precompile(Precompile.java:241)
  [INFO]  at com.google.gwt.dev.Precompile.precompile(Precompile.java:223)
  [INFO]  at com.google.gwt.dev.Precompile.precompile(Precompile.java:139)
  [INFO]  at com.google.gwt.dev.Compiler.run(Compiler.java:167)
  [INFO]  at com.google.gwt.dev.Compiler.run(Compiler.java:132)
  [INFO]  at com.google.gwt.dev.Compiler$1.run(Compiler.java:99)
  [INFO]  at com.google.gwt.dev.CompileTaskRunner.doRun(CompileTaskRunner.java:55)
  [INFO]  at com.google.gwt.dev.CompileTaskRunner.runWithAppropriateLogger(CompileTaskRunner.java:50)
  [INFO]  at com.google.gwt.dev.Compiler.main(Compiler.java:106)
  [INFO] ------------------------------------------------------------------------
  [INFO] BUILD FAILURE
  [INFO] ------------------------------------------------------------------------
  [INFO] Total time: 11.522s
  [INFO] Finished at: Fri Sep 05 11:00:36 EDT 2014
  [INFO] Final Memory: 15M/222M
  [INFO] ------------------------------------------------------------------------
  [ERROR] Failed to execute goal org.codehaus.mojo:gwt-maven-plugin:2.6.1:compile (default-cli) on project rm-ui: Command [[
  </code></pre>
  
  <p>then there is a huge classpath here ending with:</p>
  
  <pre><code>...\tholmes\.m2\repository\com\google\gwt\gwt-dev\2.6.1\gwt-dev-2.6.1.jar             
  com.google.gwt.dev.Compiler -logLevel INFO -style OBF -war C:\Users\tholmes\git\rm_ui
  \target\rm-ui-0.0.1-SNAPSHOT -localWorkers 4 -XfragmentCount -1 -sourceLevel auto -gen  C:\Users\tholmes\git\rm_ui\target\.generated com.redi2.products.rm.RevenueManager
  </code></pre>
  
  <p>]] 
      failed with status 1
          at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:216)
          at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
          at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
          at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
          at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
          at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
          at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
          at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:318)
          at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:153)
          at org.apache.maven.cli.MavenCli.execute(MavenCli.java:555)
          at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:214)
          at org.apache.maven.cli.MavenCli.main(MavenCli.java:158)
          at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
          at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
          at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
          at java.lang.reflect.Method.invoke(Method.java:606)
          at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
          at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
          at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:414)
          at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:357)</p>
  
  <p>then it says:</p>
  
  <pre><code>Caused by: org.codehaus.mojo.gwt.shell.ForkedProcessExecutionException: Command [[
  </code></pre>
  
  <p>with a huge class path, and finally ending with ...</p>
  
  <p>...\tholmes.m2\repository\com\google\gwt\gwt-dev\2.6.1\gwt-dev-2.6.1.jar com.google.gwt.dev.Compiler 
      -logLevel INFO -style OBF 
      -war C:\Users\tholmes\git\rm_ui\target\rm-ui-0.0.1-SNAPSHOT 
      -localWorkers 4 -XfragmentCount -1 
      -sourceLevel auto 
      -gen C:\Users\tholmes\git\rm_ui\target.generated com.redi2.products.rm.RevenueManager
  ]] failed with status 1
          at<br>
      org.codehaus.mojo.gwt.shell.AbstractGwtShellMojo$JavaCommand.execute(AbstractGwtShellMojo.java:485)
          at org.codehaus.mojo.gwt.shell.CompileMojo.compile(CompileMojo.java:446)
          at org.codehaus.mojo.gwt.shell.CompileMojo.doExecute(CompileMojo.java:351)
          at org.codehaus.mojo.gwt.shell.AbstractGwtShellMojo.execute(AbstractGwtShellMojo.java:172)
          at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:106)
          at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
          ... 19 more</p>
  
  <pre><code> [ERROR]
   [ERROR]
   [ERROR] For more information about the errors and possible solutions, please read the  following articles:
   [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
  </code></pre>
  
  <p>I've spent two days, and going on three trying to figure this out.<br>
  This is a project we have in our local git, and I'd rather not have to revuild a new UI project from scratch.</p>
  
  <p>Thanks!</p>