Underscores in Numeric Literals

Let’s see underscores in numeric literals in action:


package com.journaldev.util;
public class UnderscoreNumericLiterals {
	public static void main(String[] args) {
		long ccNumber = 1234_5678_9012_3456L;
		long ssn = 999_99_9999L;
		float pi = 	3.14_15F;
		long hexadecimalBytes = 0xFF_EC_DE_5E;
		long hexadecimalWords = 0xCAFE_BABE;
		long maxOfLong = 0x7fff_ffff_ffff_ffffL;
		byte byteInBinary = 0b0010_0101;
		long longInBinary = 0b11010010_01101001_10010100_10010010;
		int add = 12_3 + 3_2_1;
		System.out.println("ccNumber="+ccNumber);
		System.out.println("ssn="+ssn);
		System.out.println("pi="+pi);
		System.out.println("hexadecimalBytes="+hexadecimalBytes);
		System.out.println("hexadecimalWords="+hexadecimalWords);
		System.out.println("maxOfLong="+maxOfLong);
		System.out.println("byteInBinary="+byteInBinary);
		System.out.println("longInBinary="+longInBinary);
		System.out.println("add="+add);
	}
}

package com.journaldev.util;

public class UnderscoreNumericLiterals {

public static void main(String[] args) {

long ccNumber = 1234_5678_9012_3456L;

long ssn = 999_99_9999L;

float pi = 3.14_15F;

long hexadecimalBytes = 0xFF_EC_DE_5E;

long hexadecimalWords = 0xCAFE_BABE;

long maxOfLong = 0x7fff_ffff_ffff_ffffL;

byte byteInBinary = 0b0010_0101;

long longInBinary = 0b11010010_01101001_10010100_10010010;

int add = 12_3 + 3_2_1;

System.out.println("ccNumber="+ccNumber);

System.out.println("ssn="+ssn);

System.out.println("pi="+pi);

System.out.println("hexadecimalBytes="+hexadecimalBytes);

System.out.println("hexadecimalWords="+hexadecimalWords);

System.out.println("maxOfLong="+maxOfLong);

System.out.println("byteInBinary="+byteInBinary);

System.out.println("longInBinary="+longInBinary);

System.out.println("add="+add);

}

The above program compiles fine and here is the output:

<span style="color: #008000;"><strong><code>
ccNumber=1234567890123456
ssn=999999999
pi=3.1415
hexadecimalBytes=-1253794
hexadecimalWords=-889275714
maxOfLong=9223372036854775807
byteInBinary=37
longInBinary=-764832622
add=444
</code></strong></span>

ccNumber=1234567890123456

ssn=999999999

pi=3.1415

hexadecimalBytes=-1253794

hexadecimalWords=-889275714

maxOfLong=9223372036854775807

byteInBinary=37

longInBinary=-764832622

add=444

</code></strong></span>

Tips for Underscores in Numeric Literals

Underscores can be placed only between digits.
You can’t put underscores next to decimal places, L/F suffix or radix prefix. So 3._14, 110_L, 0x_123 are invalid and will cause compilation error.
Multiple underscores are allowed between digits, so 12___3 is a valid number.
You can’t put underscores at the end of literal. So 123_ is invalid and cause compile time error.
When you place underscore in the front of a numeric literal, it’s treated as an identifier and not a numeric literal. So don’t confuse with it.

int _10=0; int x = _10;

1
2
3
4

int _10=0;
int x = _10;
You can’t use underscores where you are expecting a String with digits. For example Integer.parseInt("12_3"); will throw java.lang.NumberFormatException.

Underscores in Numeric Literals – Java 7 Feature With Examples [Latest]

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