Instance of performance in Java -

i working on tcp server application. when message received, new instance of object representing message created. À function in messages handler called , new instance passed parameter. parameter of type "imessage" (interface message). @ point, need identify message type.

my question : in order have best performences, should add à unique identifier in each imessage instance, int, or should use instanceof ?

you asking if faster test integer field or use instanceof.

there 2 answers:

1. it depends on actual code write, , platform run on. way know sure write code (both versions) , either benchmark them, or dump native codes jit compiler emits , analyse , compare them¹.

2. the answer doesn't matter. percentage of time spent in if test in dispatching message tiny compared rest of application. (and if performance really matters you, should implementing server in c or c++.)

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^{1 - later requires deep understanding how assembly code performs. difficult topic.}