Answer: left-hand side instanceof operator : Questions « Operators « SCJP

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B. 


public class MainClass{
    public static void main(String[] argv){
      System.out.println(String instanceof String);
    }
}

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
  String cannot be resolved

  at MainClass.main(MainClass.java:3)