Operators

A school program needs reliable data and clear rules. Operators combine or compare values. A marks report can add subject scores and compare the total with a threshold; a comparison produces a boolean value.

Operators in Java are special symbols used to perform actions on variables and values. They help you do things like math calculations, compare numbers, assign values, and make decisions.

In this guide, we'll walk through all the primary types of Java operators, explaining each with easy-to-understand code examples and detailed output explanations.

• Arithmetic Operators
• Relational (Comparison) Operators
• Logical Operators
• Assignment Operators
• Unary Operators
• Bitwise Operators
• Ternary Operator

Arithmetic operators are used to perform basic mathematical operations.

public class ArithmeticExample {
    public static void main(String[] args) {
        int a = 10, b = 3;
        System.out.println("a + b = " + (a + b));
        System.out.println("a - b = " + (a - b));
        System.out.println("a * b = " + (a * b));
        System.out.println("a / b = " + (a / b));
        System.out.println("a % b = " + (a % b));
    }
}

a + b = 13
a - b = 7
a * b = 30
a / b = 3
a % b = 1

These operators assign values to variables.

public class AssignmentExample {
    public static void main(String[] args) {
        int a = 5;
        a += 3;
        a *= 2;
        System.out.println("Final value of a: " + a);
    }
}

Final value of a: 16

Relational operators compare two values and return a boolean result.

public class RelationalExample {
    public static void main(String[] args) {
        int x = 10, y = 20;
        System.out.println("x == y: " + (x == y));
        System.out.println("x != y: " + (x != y));
        System.out.println("x < y: " + (x < y));
        System.out.println("x > y: " + (x > y));
    }
}

x == y: false
x != y: true
x < y: true
x > y: false

Logical operators help in combining multiple boolean expressions.

public class LogicalExample {
    public static void main(String[] args) {
        int a = 5, b = 10;
        System.out.println((a > 0) && (b > 0));
        System.out.println((a > 0) || (b < 0));
        System.out.println(!(a == b));
    }
}

true
true
true

Unary operators operate on a single operand.

public class UnaryExample {
    public static void main(String[] args) {
        int a = 5;
        System.out.println("a = " + a);
        System.out.println("++a = " + (++a));
        System.out.println("a-- = " + (a--));
        System.out.println("Final a = " + a);
    }
}

a = 5
++a = 6
a-- = 6
Final a = 5

Bitwise operators work on bits and perform bit-by-bit operations.

public class BitwiseExample {
    public static void main(String[] args) {
        int a = 5, b = 3;
        System.out.println("a & b: " + (a & b));
        System.out.println("a | b: " + (a | b));
        System.out.println("a ^ b: " + (a ^ b));
        System.out.println("~a: " + (~a));
        System.out.println("a << 1: " + (a << 1));
        System.out.println("a >> 1: " + (a >> 1));
    }
}

a & b: 1
a | b: 7
a ^ b: 6
~a: -6
a << 1: 10
a >> 1: 2

• Operator precedence matters – always use parentheses if unsure. We cover this in our very next topic.
• Logical operators short-circuit (&& and ||) – they may skip evaluating the second condition.
• Bitwise and logical operators are not the same (& vs &&).
• Unary post-increment and pre-increment behave differently.

Use equals to compare String contents. The == operator compares object references rather than generally comparing their text.

Before running this Java program, write down each line you expect to see. Identify the value, branch, object or exception responsible for each line. Then explain whether the following assumption is valid: Use equals to compare String contents.

Java 17 · Main.java · complete practice program

public class Main  {
  public static void main(String[] args)  {
    int total = 35 + 40;
    System.out.println(total >= 70);
  }
}

Now change one thing: Change the two marks to 30 and 35. Predict the new behavior before checking the worked variation.

Java 17 · Main.java · source repeated for this answer

public class Main  {
  public static void main(String[] args)  {
    int total = 35 + 40;
    System.out.println(total >= 70);
  }
}

Expected output

true

Operators combine or compare values. A marks report can add subject scores and compare the total with a threshold; a comparison produces a boolean value.

Use equals to compare String contents. The == operator compares object references rather than generally comparing their text.

Run with javac Main.java, then java Main. The declaration of Main names the class; main starts the example, and println writes a complete output line.

Worked variation: Change the two marks to 30 and 35. Their total is 65, so total >= 70 is false.

Operators combine or compare values. A marks report can add subject scores and compare the total with a threshold; a comparison produces a boolean value. Use equals to compare String contents. The == operator compares object references rather than generally comparing their text.

Related explanations: Java Variables, Java If Statement - Syntax and Examples, Java Class - Blueprint of Objects, Exceptions in Java Introduction.

Supporting documentation: Official Java learning guide and Java 17 language specification.