Reports use of the synchronized modifier on methods.
There are several reasons a synchronized modifier on a method may be a bad idea:
First, as a rule as little work as possible should be performed under a lock.
Therefore it is often better to use a synchronized statement and move as much of the methods code outside the
synchronized region.
Second, it makes synchronization part of the external interface of the class.
This makes a future change to a different locking mechanism difficult.
Third, it makes it hard to track just who is locking on a given object.
And fourth, it makes a denial-of-service attack possible, either on purpose or it can happen easily by accident when subclassing.
As an alternative, consider
synchronizing on a private final lock object, access to which can be completely controlled.