Literals in Java: A Complete Guide with Best Practices
Last updated on 04th Jun 2020, Blog, General
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What are Literals in Java?
They are used to represent the constant value. Literals are source code representation of a fixed value or the sequence of characters which represents the constant value that is to be stored in a variable.
There are five types of literals in Java.
- Integer Literals
- Boolean Literals
- Character Literals
- String Literals
- Floating Point Literals
Integer Literals in Java
There are four primitive data types present in integer literals, they are a byte, short, long, int and we can represent these in 4 ways:
Decimal literals:
Any number from 0-9 are allowed here.
Ex: int a=100;
Octal literals:
Any number from 0-7 is allowed here, but the value should start from 0 only.
Ex: int b=035;
Hexa-decimal literals:
Here the digit from 0-9 and characters from a-f are allowed. The value can be a combination of characters and digit. We can use both uppercase and lower-case characters here, for this it is not case-sensitive. This value should start from 0X or 0x.
Ex: int c=0X238ce;
Binary literals:
It consists of only two-digit 0 and 1, but the value should start from 0b or 0B.
Ex: int d=0B1101;
See the following program.
- public class Integer {
- public static void main(String args[]) {
- int a = 100; // decimal literals
- int b = 035; // octal literals
- int c = 0X238ce; // hexadecimal literals
- int d = 0B1101; // binary literals
- System.out.println(a);
- System.out.println(b);
- System.out.println(c);
- System.out.println(d);
- }
- }
See the following output.
Floating-point literals
Floating-point literals only contain decimal values with a fractional component. It consists of a double and floats data type.
Ex:
- double a=3.24343;
- Float b=45.34f;
See the following program.
- public class Floating {
- public static void main(String[] args) {
- double a = 3.24343;
- float b = 45.34f;
- System.out.println(a);
- System.out.println(b);
- }
- }
See the following output.
By default, every floating-point literal is of double type, and hence we cant assign directly to float variable. But we can specify floating-point literal as float type by suffixed with f or F. We can specify explicitly floating-point literal as double type by suffixed with d or D., and Of course, this convention is not required.
Character Literals
It is a 16-bit Unicode, and it is enclosed in single quotes whereas in the string is enclosed in double quote.
Ex:
- Char ch=’a’;
- Char ch1=’#’;
- Char ch2=’4’;
For the char data types, we can define the literals in 4 ways:
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Single quote
We can specify literal to a char data type as a single character within a single quote.
- char ch = ‘a’;
Char literal as Integral literal
We can define the char literal as an integral literal which represents the Unicode value of a character and those integral literals can be defined either in the Decimal, Octal, and Hexadecimal forms.
- But the final allowed range is 0 to 65535.
- char ch = 062;
Unicode Representation
We can define the char literals in Unicode representation ‘\uxxxx’. Here xxxx represents 4 hexadecimal numbers.
- char ch = ‘\u0061’;
- Here /u0061 represent a.
Escape Sequence
Every escape character can be specified as char literals.
- char ch = ‘\n’;
See the following program.
- public class Test {
- public static void main(String[] args) {
- char ch1 = ‘a’;
- char ch2 = ‘#’;
- char ch3 = ‘4’;
- System.out.println(ch3);
- System.out.println(ch2);
- System.out.println(ch3);
- }
- }
See the output.
String Literals
They are the sequence of characters that are enclosed in double-quotes, and it can be a sentence too.
Any sequence of the characters within the double quotes is treated as String literals.
- String str1=” how are you?”;
- String str2=” I’m good thanks!”;
See the following program.
- public class Test {
- public static void main(String[] args) {
- String str1 = “how are you?”;
- String str2 = ” I’m good thanks!”;
- System.out.println(str1);
- System.out.println(str2);
- }
- }
See the output:
String literals may not contain unescaped newline or linefeed characters. However, the Java compiler will evaluate compile-time expressions.
Boolean literals
Only two values can be represented in Boolean literals, i.e. either true or false. These two values can be assigned to a variable. These true and false are case sensitive in java.
Ex:
- boolean flg1=” true”;
- boolean flg2=” false”;
See the program of Boolean literals.
- public class Boolean {
- public static void main(String args[]) {
- boolean flg1 = true;
- boolean flg2 = false;
- System.out.println(flg1);
- System.out.println(flg2);
- }
- }
See the output:
- When we are performing concatenation operations, then the values in brackets are concatenated first. Then the values are concatenated from left to right.
- We should be careful when we are mixing character literals and integers in String concatenation operations, and this type of operation is known as Mixed Mode operation.