Boolean type (boolean)

Boolean type

boolean represents one of two values: true or false. It is used for logical expressions and control flow.

Declaration:

boolean isJavaFun = true;
boolean isRaining = false;

Common uses:

• Conditions:

if (isJavaFun) {
    System.out.println("Java is fun!");
}

• Loop controls:

boolean keepRunning = true;
while (keepRunning) {
    // do something
    keepRunning = false; // stop condition
}

• Return values from methods:

public boolean isEven(int number) {
    return number % 2 == 0;
}

Short‑circuit evaluation: && and || evaluate only the necessary operands.

int x = 5;
if (x > 0 && (10 / x) > 1) { // safe: second part only if x > 0
    // ...
}

Note: Java does not treat integers as booleans (unlike C/C++). You cannot write if (x); you must write if (x != 0).