code: @Override
      public void sawOpcode(int seen) {
          if (seen == Const.INVOKEVIRTUAL) {
              String className = getClassConstantOperand();
              String methodName = getNameConstantOperand();
              String methodSig = getSigConstantOperand();
  
              FQMethod methodInfo = new FQMethod(className, methodName, methodSig);
              if (oldMethods.contains(methodInfo)) {
                  bugReporter.reportBug(new BugInstance(this, BugType.NCMU_NON_COLLECTION_METHOD_USE.name(), NORMAL_PRIORITY).addClass(this).addMethod(this)
                          .addSourceLine(this));
              }
          }
      }
docs: implements the visitor to look for method calls that are one of the old pre-collections1.2 set of methods
  
  @param seen
  the currently parsed opcode