Literals in Java

What is a Literal?

• A literal is a constant value written directly in the code.
• Example:

  int x = 10;   // 10 is a literal

Types of Literals

1. Integer Literals

• Can be written in different number systems:

  int num1 = 0b101;      // Binary (prefix 0b) → 5
  int num2 = 0x78;       // Hexadecimal (prefix 0x) → 120
  int num3 = 1000_000_00; // Underscore for readability → 100000000

2. Floating-Point Literals

• Can be written using decimal or scientific notation:

  double num4 = 12e10;   // 12 × 10^10
  float f = 5.6f;        // float needs 'f'
  double d = 5.6;        // double by default

3. Character Literals

• Written inside single quotes:

  char c1 = 'a';
  char c2 = 65;     // Unicode/ASCII → 'A'
  char c3 = '\u0041'; // Unicode literal → 'A'

4. Boolean Literals

• Only two possible values:

  boolean b1 = true;
  boolean b2 = false;

Example Program

public class Hello {
    public static void main(String[] args) {
        int num1 = 0b101;         // Binary → 5
        int num2 = 0x78;          // Hexadecimal → 120
        int num3 = 1000_000_00;   // Readable large number
        double num4 = 12e10;      // Scientific notation
        char c = 'a';
        c = (char)(c + 1);        // 'b'

        boolean flag = true;
        System.out.println(num1);
        System.out.println(num2);
        System.out.println(num3);
        System.out.println(num4);
        System.out.println(c);
        System.out.println(flag);
    }
}

Key Notes:

• Use underscores (_) in numbers for readability.
• 0b → binary, 0x → hexadecimal.
• Floating literals can use scientific notation (e/E).
• Characters can be represented as Unicode/ASCII values.