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The ! Operator
This operator is known as “NOT” or “Logical NOT” operator. It is a unary operator because it works only on one
operand. The outcome of this operator is false, if the condition is satisfied and if the condition does not satisfy,
then the outcome of the operator is true. In other words, it reverses the output of the condition. For example, if
we take the expression !(a>b), then the output will be:
Condition 1 Condition 2 !(Condition 1 && Condition 2)
(a>b) (b>c) !((a>b)&&(b>c))
0 / false 1 / true 1 / true
1 / true 0 / false 1 / true
Note: Relational expression works before the logical part, this is because the precedence of a
Relational Operator is higher than Logical Operator.
Java evaluates logical operators based on the following order of precedence:
NOT (!) – highest precedence
AND (&&)
OR (||) – lowest precedence
This means that in complex expressions, the ! operator will be evaluated first, followed by &&,
and finally ||.
Program 18 Write a program to demonstrate the use of logical operators.
1 public class logical_operator
2 {
3 public static void main()
4 {
5 boolean a = true;
6 boolean b = false;
7
8 System.out.println("a && b = " + (a&&b));
9 System.out.println("a || b = " + (a||b) );
10 System.out.println("!(a && b) = " + !(a && b));
11 }
12 }
Operators in Java 101

