I was seeing an issue where an EnclosingAttribute didn't have a method index (it was zero).
This caused the compact/clone to fail.

Ths was code generated with JDK5 and it looked it was recording the enclosing
class rather than an method

public class MyClass
{
 public class InnerClass
 {
 }
}

User: adrian
 Date: 06/02/06 05:02:34

 Modified: src/main/javassist/bytecode EnclosingMethodAttribute.java
 Log:
 Compacting/clone has a problem when the method index is zero.
 This looks like an inner class trying to describe its outer class rather
 than a method.

 Revision Changes Path
 1.4 +20 -0 javassist/src/main/javassist/bytecode/EnclosingMethodAttribute.java

 (In the diff below, changes in quantity of whitespace are not shown.)

 Index: EnclosingMethodAttribute.java
 ===================================================================
 RCS file: /cvsroot/jboss/javassist/src/main/javassist/bytecode/EnclosingMethodAttribute.java,v
 retrieving revision 1.3
 retrieving revision 1.4
 diff -u -b -r1.3 -r1.4
 --- EnclosingMethodAttribute.java 11 Jan 2006 06:45:56 -0000 1.3
 +++ EnclosingMethodAttribute.java 6 Feb 2006 10:02:34 -0000 1.4
 @@ -56,6 +56,24 @@
 }

 /**
 + * Constructs an EnclosingMethod attribute.
 + *
 + * @param cp a constant pool table.
 + * @param className the name of the innermost enclosing class.
 + */
 + public EnclosingMethodAttribute(ConstPool cp, String className) {
 + super(cp, tag);
 + int ci = cp.addClassInfo(className);
 + int ni = 0;
 + byte[] bvalue = new byte[4];
 + bvalue[0] = (byte)(ci >>> 8);
 + bvalue[1] = (byte)ci;
 + bvalue[2] = (byte)(ni >>> 8);
 + bvalue[3] = (byte)ni;
 + set(bvalue);
 + }
 +
 + /**
 * Returns the value of <code>class_index</code>.
 */
 public int classIndex() {
 @@ -105,6 +123,8 @@
 * class names.
 */
 public AttributeInfo copy(ConstPool newCp, Map classnames) {
 + if (methodIndex() == 0)
 + return new EnclosingMethodAttribute(newCp, className());
 return new EnclosingMethodAttribute(newCp, className(),
 methodName(), methodDescriptor());
 }