Description Art Dyer 2006-10-04 19:39:20 EDT

Accessing a static field in a non-static way can produce code that causes a VerifyError (Inconsistent stack height).

  public class NonStaticAccessToStatic
  {
    public static String s;
  
    public static void main(String[] args) throws Throwable
    {
      if (args.length == 0)
      {
        Class c = Class.forName("NonStaticAccessToStatic");
        // The object returned by newInstance is left on the stack even
        // though it is not needed to access field s.
        String x = ((NonStaticAccessToStatic) c.newInstance()).s;
        System.out.println(x);
      }
      // At this point the stack depth is 1 if the conditional was true,
      // but 0 if it was false.
      System.out.println();
    }
  }

C:\temp> java NonStaticAccessToStatic
java.lang.VerifyError: (class: NonStaticAccessToStatic, method: main signature: ([Ljava/lang/String;)V) Inconsistent stack height 1 != 0
Exception in thread "main" 

C:\temp> java -version
java version "1.5.0_06"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-b05)
Java HotSpot(TM) Client VM (build 1.5.0_06-b05, mixed mode, sharing)