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Java find output programs (Autoboxing & Unboxing) | set 2

Find the output of Java programs | Autoboxing & Unboxing | Set 2: Enhance the knowledge of Java Autoboxing & Unboxing concepts by solving and finding the output of some Java programs.
Submitted by Nidhi, on February 04, 2021

Question 1:

public class BoxingEx {
  public static void main(String[] args) {
    char charVar = 'A';

    Char Obj = charVar;

    System.out.println(Obj);
  }
}

Output:

/BoxingEx.java:5: error: cannot find symbol
    Char Obj = charVar;
    ^
  symbol:   class Char
  location: class BoxingEx
1 error

Explanation:

The above program will generate a syntax error because we used wrapper class Char instead of Character. The Char class is not available in Java. The correct code is given below,

public class BoxingEx
{
     public static void main(String []args)
     {
        char charVar = 'A';
        
        Character  Obj = charVar;

        System.out.println(Obj);
     }
}

Question 2:

public class BoxingEx {
  public static void main(String[] args) {
    char charVar = 'A';

    Character Obj = charVar;
    Obj++;

    System.out.println(Obj);
  }
}

Output:

B

Explanation:

In the above program, we created a local variable charVar initialized with 'A'.

Character  Obj = charVar;
Obj++;

In the above statement we auto-box the variable charVar into wrapper class Character, and then increase the value of Object Obj using post-increment operator. Then the value of the object Obj will 'B' and that will be printed on the console screen.

Question 3:

public class BoxingEx {
  public static void main(String[] args) {
    long value = 'A';

    Long Obj = value;

    long value1 = Obj.longValue();

    System.out.println(value1);
  }
}

Output:

65

Explanation:

In the above program, we created a local variable value initialized with 'A'. Then auto-box value into object Obj. After that un-box the value of variable value and assigned to the variable value1 and then print variable value1 that will print 65, which is the ASCII value of character 'A'.

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