Boolean Logical Operators

The Boolean logical operators operate only on boolean operands.

Operator	Result
&	Logical AND
\|	Logical OR
^	Logical XOR (exclusive OR)
\|\|	Short-circuit OR
&&	Short-circuit AND
!	Logical unary NOT
&=	AND assignment
\|=	OR assignment
^=	XOR assignment
==	Equal to
!=	Not equal to
? :	Ternary if-then-else

The following table shows the effect of each logical operation:

A	B	A \| B	A & B	A ^ B	!A
False	False	False	False	False	True
True	False	True	False	True	False
False	True	True	False	True	True
True	True	True	True	False	False

The following program demonstrates the boolean logical operators.

  

public class Main {
  public static void main(String args[]) {
    boolean a = true;
    boolean b = false;
    boolean c = a | b;
    boolean d = a & b;
    boolean e = a ^ b;
    boolean f = (!a & b) | (a & !b);
    boolean g = !a;
    System.out.println(" a = " + a);
    System.out.println(" b = " + b);
    System.out.println(" a|b = " + c);
    System.out.println(" a&b = " + d);
    System.out.println(" a^b = " + e);
    System.out.println("!a&b|a&!b = " + f);
    System.out.println(" !a = " + g);

  }
}

The output:

  
 a = true
 b = false
 a|b = true
 a&b = false
 a^b = true
!a&b|a&!b = true
 !a = false

Short-Circuit Logical Operators

The OR operator results in true when one operand is true, no matter what the second operand is.

The AND operator results in false when one operand is false, no matter what the second operand is.

If you use the || and &&, Java will not evaluate the right-hand operand when the outcome can be determined by the left operand alone.

The following code shows how you can use short-circuit logical operator to ensure that a division operation will be valid before evaluating it:

  
public class Main {
  public static void main(String[] argv) {
    int denom = 0;
    int num = 3;
    if (denom != 0 && num / denom > 10) {
      System.out.println("Here");
    } else {
      System.out.println("There");
    }
  }
}

The output:


There

The following code uses a single & ensures that the increment operation will be applied to e whether c is equal to 1 or not.

  
public class Main {
  public static void main(String[] argv) {
    int c = 0;
    int e = 99;
    int d = 0;
    if (c == 1 & e++ < 100)
      d = 100;

    System.out.println("e is " + e);
    System.out.println("d is " + d);
  }
}

The output:


e is 100
d is 0

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