Does initialization of a variable to 'null' take up memory?

Hi,
Does initialization of a variable to 'null' take up memory?
For ex:
String str = null;
Then, will the str take up memory?
Thanks & Regards,
Jags.

I suppose that you are referring to local variables, not instance variables.
String str;It takes only a slot (4 bytes) in stack. If the variable is unused, some compilers will not reserve the 4 bytes. For speed and alignment reasons it is not forbidden to occupy 8 bytes in the stack for the slot. (For instance, 64-bit processors, and some 32-bit processors, usually require that these variables start in memory addresses that are multiples of 8).
String str = null;It takes a slot (4 bytes) in stack, and some opcodes in program memory.
If the variable is not used after, the compiler is free to remove the assignment and not reserving the 4 bytes.
Memory calculations are more difficult than you can think, because JIT compilers are free to use a lot of memory in special structures and restructure your data. So a seemingly innocent String str = null may not occupy memory, or use a lot of it.

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