CODEWITHSUNDEEP
javamultithreadingsocketsthread-safety
JRR
JRR

Reputation: 6152

Is Java socket multi-thread safe?

If I have multiple Java threads writing to the same Socket instance simultaneously, will that affect the integrity of the objects that are read from the same socket? I.e., whether the contents of the objects will be messed up etc. It's fine for the ordering of objects to be random.

Upvotes: 17

Views: 9791

Answers (2)

Cratylus
Cratylus

Reputation: 54074

If I have multiple Java threads writing to the same Socket instance simultaneously

You will be writing to the same OutputStream from multiple threads.
What makes you think that it is a good idea without synchronization? If you started writing to a file from multiple threads simultaneously without synchronization would you expect the file to contain anything meaningfull?

Upvotes: 5

NPE
NPE

Reputation: 500357

In general, there are no guarantees. Bits of different objects could well end up getting interleaved on the wire, rendering the result indecipherable. Therefore, you need to provide external synchronization.

It is interesting to note that even a single socket write at the OS level is not necessarily atomic. For further discussion, see Is it safe to issue blocking write() calls on the same TCP socket from multiple threads? and Be careful with the sendmsg() family of functions.

Upvotes: 16

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