CODEWITHSUNDEEP
javaconcurrencytimer
ripper234
ripper234

Reputation: 230008

Is Java's Timer task guaranteed not to run concurrently?

new Timer(...).schedule(task)

Is task guaranteed to be run by a single thread at any given time?

Upvotes: 7

Views: 3890

Answers (3)

Ray
Ray

Reputation: 1585

Indeed. They all run on a same background thread corresponded to the Timer object in sequence. BUT two different Timer instances will run (I believe) on different threads, so you have to save reference to a timer object to schedule more tasks sequentialy.

Upvotes: 0

Maurice Perry
Maurice Perry

Reputation: 32831

There is a single thread per Timer, so the answer to your question is yes

Upvotes: 4

Thilo
Thilo

Reputation: 262474

From the Javadoc

Corresponding to each Timer object is a single background thread that is used to execute all of the timer's tasks, sequentially. Timer tasks should complete quickly. If a timer task takes excessive time to complete, it "hogs" the timer's task execution thread. This can, in turn, delay the execution of subsequent tasks, which may "bunch up" and execute in rapid succession when (and if) the offending task finally completes.

So, yes, you get a new Thread (separate from the caller's thread). Every task in that timer shares the same thread.

Upvotes: 10

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