Java For Dummies Quick Reference

Boolean Expressions

A Boolean expression is a Java expression that, when evaluated, returns a Boolean value: true or false. Boolean expressions are used in conditional statements, such as if, while, and switch.

The most common Boolean expressions compare the value of a variable with the value of some other variable, a constant, or perhaps a simple arithmetic expression. This comparison uses one of the following relational operators:

Operator	Description
==	Returns true if the expression on the left evaluates to the same value as the expression on the right.
!=	Returns true if the expression on the left does not evaluate to the same value as the expression on the right.
<	Returns true if the expression on the left evaluates to a value that is less than the value of the expression on the right.
<=	Returns true if the expression on the left evaluates to a value that is less than or equal to the expression on the right.
>	Returns true if the expression on the left evaluates to a value that is greater than the value of the expression on the right.
>=	Returns true if the expression on the left evaluates to a value that is greater than or equal to the expression on the right.

For more information, see Variables and Constants.

A basic Boolean expression has this form:

expression relational-operator expression

Java evaluates a Boolean expression ...