Literal in Java

A literal is a fixed value that is stored or assigned to variables. They are represented directly in code without requiring computation. Literals can be assigned to a variable of a primitive type.

Example

boolean result = true;
char c = 'a';
byte b = 100;
short s = 10000;
int i = 1000000;

Integer Literals

An integer literal that ends with the letter L or l is of type long otherwise it is of type int. It is recommended to use the upper case letter L because the lower case letter l is hard to distinguish from the digit 1.

Example: 10000004543L

Integer literals can be expressed by the following number systems:

• Decimal — Decimal is the base-10 number system that we use every day for calculations. It consists of the numbers from 0 to 9.
• Hexadecimal — The numeral system that is a made up of 16 symbols, 0 through 9 and the letters A through F. It is a base 16 numerical system. It is often shortened to hex.
• Binary — The numeral system that is a made up of 2 symbols (0 and 1). It is a base 2 numerical system. The binary literals can be created in Java SE 7 and later.

In Java literals, the prefix 0x indicates hexadecimal and 0b indicates binary. For example:

Floating-Point Literals

A float value that ends with the letter F or f is a floating-point literal, otherwise it is of double type. The double literal can optionally end with the letter D or d (by convention, it is omitted).

For scientific notation, the floating point types (float and double) can also be expressed using E or e.

Example

double d1 = 123.4;

Here is the same value as d1, but in scientific notation:

double d1 = 1.234e2;
float f1 = 123.4f;

Character and String Literals

To assign char literals, use 'single quotes' and for String literals use "double quotes". The char and String Literals may contain any Unicode (UTF-16) characters. For example:

char a = '\u0001';

String a = "\u0001";

Following are some of the special escape sequences for char and String literals in Java:

The null Literals

The null literal is used to indicate that the value or object is unavailable. It can be assigned as a value to any reference type variables. However, it cannot be assigned to variables of primitive types.

Example

String name = null;

The class literal

The class literal is formed by using a type name, followed by .class.

Example

package com.example;

public class ClassLiteralExample {

    public static void main(String[] args) {
        Class<String> a = String.class;
        Class<Long> b = long.class;
        System.out.println(a);
        System.out.println(b);
    }
}

Output

Underscore Characters in Numeric Literals

Since Java 7, underscore characters _ can be inserted between digits in a numerical literal. The use of underscore between numbers may help to improve the readability of a code by separating groups of digits in numeric literals.

Example

long creditCardNumber = 1234_5678_9012_3456L;
long socialSecurityNumber = 999_99_9999L;
float pi = 3.14_15F;

We can place underscores only between digits; we cannot place underscores in the following places:

• Underscores cannot be inserted adjacent to a decimal point in a floating point literal.

For example: float pi = 3._1415F; is invalid.

• Underscores cannot be placed prior to an F or L suffix.

For example: long socialSecurityNumber = 999_99_9999_L; is invalid

• Underscores cannot be placed in positions where a string of digits is expected.