What is the &= operator for in Java

Question

The Java tutorials here mention that &= is an assignment operator but doesn't seem to mention what it does.

What does &= do?

Answer 1

a &= x

is equivalent to

a = (type of a)(a & x)

which in turn is a

• bitwise AND of a and x in the case where a and x are integers or a
• non short-circuiting logical AND in the case of a and x being booleans (which means that x will be evaluated in any case here, even if a is false).

There are several other binary operators which can be used with similar semantics, like +=, -=, *=, /=, %=, |=, <<=, ...