@ Override public void visitClassContext ( ClassContext classContext ) { try { JavaClass cls = classContext . getJavaClass ( ) ; if ( cls . getMajor ( ) >= Const . MAJOR_1_4 ) { stack = new OpcodeStack ( ) ; regValueType = new HashMap < Integer , State > ( ) ; super . visitClassContext ( classContext ) ; } } finally { stack = null ; regValueType = null ; } }
implements the visitor to make sure the class is at least java 1 . 4 and to reset the opcode stack