Binary literals in Java

Integer (byte, short, int or long) literals in Java can be expressed using one of the following three formats

int n08 = 052;
int n10 = 42;
int n16 = 0x2A;

Here all three variables represent the same number. There is no out-of-the-box binary presentation. Nevertheless, it is desirable sometimes to specify constants in easy readable binary form, for example for bit masks.

The answer from Ed Swangren works fine.

int n02 = Integer.parseInt("101010", 2);

Here is another example:
public final static long mask11 =
Long.parseLong("00000000000000000000100000000000", 2);

I used long instead of int and added the modifiers to clarify possible usage of the presentation as a bit mask. There are, though, two inconveniences with this approach.

1. The direct typing of all those zeroes is error prone


2. The result is not available in decimal or hex format at the time of development

I can suggest alternative approach

public final static long mask11 = 1L << 11;

This expression makes it obvious that the 11th bit is 1 (count starts from 0, from the right to the left); and when you hover mouse cursor, the tooltip

long YourClassName.mask11 = 4096 [0x1000]

appears in Eclipse. You can define more complicated constants like:

public final static long n02 = mask05 | mask03 | mask01;

or explicitly

public final static long n02 = (1L<<5)|(1L<<3)|(1L<<1);

The value of the variable n02 will still be available in Eclipse at development time.