What's the purpose to bit-shift int value by zero?

Question

Looking to the source code of java.nio.DirectByteBuffer class, I have found this:

if ((length << 0) > Bits.JNI_COPY_TO_ARRAY_THRESHOLD) ....
         


        

Answer 1

The i << 0 is plainly redundant. There is no good reason for a Java programmer to write this code deliberately.

I'd say that this code is:

• written by someone who wasn't thinking,
• written by someone who doesn't understand what the << operator does,
• the result of some semi-mechanical refactoring, or
• originally produced by some sort of code generator or translator.

However, there's a good chance that the bytecode or JIT compiler will optimize this away, or that it won't impact significantly on performance anyway.