CODEWITHSUNDEEP
javaarraysmultithreadingthread-safety
GotoFinal
GotoFinal

Reputation: 3675

Java, editing array from multiple threads

I have many byte arrays of size 4096 (16x16x16), and I want editing them from many threads in one time, there is small chance that any element will be written in one time by more than one thread, and almost impossible that more than 3 will be accessing it (one of elements) in one time (write or read).
But whole array can be accessed by many threads in one time.

Can this cause any problems? If yes, then how to fix/avoid them?
I know that reading should be safe, and I hear about some problems with writing
Code need be fast (real-time based stuff) so I can't synchronize that, and I can't use any ArrayList, because that will cause problems with memory. (There will be like 1000-20000 (or even more) arrays like that)

Upvotes: 2

Views: 659

Answers (1)

Damian Nikodem
Damian Nikodem

Reputation: 1289

Every time someone says real time in the same sentence as Java it peaks my interest because real time has a specific meaning that most people don't understand ( oracle / sun have a real time jvm available for purchase )

But I digress , array reads and writes are atomic, therefore thread safe. 2 threads cannot write to the array at the same time because the operation cannot get broken down to anything smaller ( allowing a scheduler to interrupt halfway through ) As long as you are careful ( e.g. Are not reading a value, doing some math and then writing it back to the array and expecting the the value at the given index to remain the same )

So in short there is nothing stopping you from doing this as long as your logic around it is also thread safe.

Upvotes: 1

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