Java Language Tutorial => Using underscore to improve readability

Example

Since Java 7 it has been possible to use one or more underscores (_) for separating groups of digits in a primitive number literal to improve their readability.

For instance, these two declarations are equivalent:

Java SE 7

int i1 = 123456;
int i2 = 123_456;
System.out.println(i1 == i2); // true

This can be applied to all primitive number literals as shown below:

Java SE 7

byte color = 1_2_3;
short yearsAnnoDomini= 2_016;
int socialSecurtyNumber = 999_99_9999;
long creditCardNumber = 1234_5678_9012_3456L;
float piFourDecimals =  3.14_15F;
double piTenDecimals =  3.14_15_92_65_35;

This also works using prefixes for binary, octal and hexadecimal bases:

Java SE 7

short binary= 0b0_1_0_1;
int octal = 07_7_7_7_7_7_7_7_0;
long hexBytes = 0xFF_EC_DE_5E;

There are a few rules about underscores which forbid their placement in the following places:

At the beginning or end of a number (e.g. _123 or 123_ are not valid)
Adjacent to a decimal point in a floating point literal (e.g. 1._23 or 1_.23 are not valid)
Prior to an F or L suffix (e.g. 1.23_F or 9999999_L are not valid)
In positions where a string of digits is expected (e.g. 0_xFFFF is not valid)

PDF - Download Java Language for free

Previous Next

Java Language

Fastest Entity Framework Extensions

Example

Got any Java Language Question?

Java Language

Java Language Literals Using underscore to improve readability

Fastest Entity Framework Extensions

Example

Got any Java Language Question?