Update java-multiple-choice-questions-answers.md

Author: learning-zone

java-multiple-choice-questions-answers.md

@@ -269,4 +269,12 @@ C. Two
 Explanation: Objects have instance methods while primitives do not. Since int is a primitive, you
 cannot call instance methods on it. Integer and String are both objects and have
 instance methods
-```
+```
+#### Q. Which of the following does not compile?
+A. int num = 999;  
+B. int num = 9_9_9;  
+C. int num = _9_99;  
+D. None of the above; they all compile.  
+```
+C. int num = _9_99; 
+```