Which one is a valid declaration of a boolean?

Which one is a valid declaration of a boolean?

2) Which of these can not be used for a variable name in Java?

3) In Java, the word true is ................

4) What will be the output for the below code ?

public class Test
  { 
       public static void main(String[] args)
  {
       byte i = 128;
       System.out.println(i); 
       } 
 }

5) Which of these values can a boolean variable contain?