Operators - Objects First with Java: A Practical Introduction Using BlueJ - page 509

In addition,

! not

takes a single boolean expression and changes it from true to false and vice versa.

C.3 Short-circuit operators

Both && and || are slightly unusual in the way they are applied. If the left operand of && is
false , then the value of the right operand is irrelevant and will not be evaluated. Similarly, if
the left operand of || is true , then the right operand is not evaluated. Thus, they are known as
short-circuit operators.