Java™ How To Program (Early Objects), Tenth Edition

Lock and Condition vs. the synchronized Keyword

In some applications, using Lock and Condition objects may be preferable to using the synchronized keyword. Locks allow you to interrupt waiting threads or to specify a timeout for waiting to acquire a lock, which is not possible using the synchronized keyword. Also, a Lock is not constrained to be acquired and released in the same block of code, which is the case with the synchronized keyword. Condition objects allow you to specify multiple conditions on which threads may wait. Thus, it’s possible to indicate to waiting threads that a specific condition object is now true by calling signal or signallAll on that Condition object. With synchronized, there’s no way to explicitly state the condition ...