@Override
    public void visitClassContext(ClassContext classContext) {
        try {
            stack = new OpcodeStack();
            nodeCreations = new HashMap<>();
            nodeStores = new HashMap<>();
            super.visitClassContext(classContext);
        } finally {
            stack = null;
            nodeCreations = null;
            nodeStores = null;
        }
    }
@ Override public void visitClassContext ( ClassContext classContext ) { try { stack = new OpcodeStack ( ) ; nodeCreations = new HashMap < > ( ) ; nodeStores = new HashMap < > ( ) ; super . visitClassContext ( classContext ) ; } finally { stack = null ; nodeCreations = null ; nodeStores = null ; } }
implements the visitor to create and clear the stack, node creations and store maps

@param classContext
the context object for the currently parsed class