Using the same expressions as both arguments to the following binary expressions is usually a mistake:

• a && a, a || a, a & a, or a | a is equivalent to a
• a <= a, a >= a, or a == a is always true
• a < a, a > a, a != a, or a ^ a is always false
• a / a is always 1
• a % a or a - a is always 0

If the expression has side-effects, consider refactoring one of the expressions with side effects into a local. For example, prefer this:

// check twice, just to be sure
boolean isTrue = foo.isTrue();
if (isTrue && foo.isTrue()) {
  // ...
}

to this:

if (foo.isTrue() && foo.isTrue()) {
  // ...
}