java.lang.Thread.sleep()
that occur inside loops.
Such calls are indicative of "busy-waiting". Busy-waiting is often inefficient, and may result in unexpected deadlocks as busy-waiting threads do not release locked resources.
Example:
class X {
volatile int x;
public void waitX() throws Exception {
while (x > 0) {
Thread.sleep(10);//warning: Call to 'Thread.sleep()' in a loop, probably busy-waiting
}
}
}