title: java debug interface:get value of ObjectReference
body: <pre><code>Exception in thread "main" java.lang.IllegalArgumentException: Attempt to use non-static field with ReferenceType
  </code></pre>
  
  <p>i trace the code which like below:</p>
  
  <pre><code>  if(!var5.isStatic()) {
              throw new IllegalArgumentException("Attempt to use non-static field with ReferenceType");
          }
  </code></pre>
  
  <p>and my Class is:</p>
  
  <pre><code>public class App {
  private String version;
  private int system;}
  </code></pre>
  
  <p>i know is not static,but i want to get the value of version,but the type of value is com.sun.jdi.ObjectReference,so how could i get the value of version?</p>