Differences in performance between static and non-stationary finite primitive fields in Java

Question

I recently came across a class in which the following field was declared:

private final int period = 1000; 

In this particular case, the author assumed that it is also static, and since the value cannot be changed at any point, there was no real functional reason not to declare it static, but I wondered how Java handles final and final static primitives.

In particular:

1) How are final static primitives stored? Are they simply compiled directly into the expressions in which they are used?

2) If they are actually reserved for storage, should each instance of the containing class maintain a reference to this location? (in this case, for primitives less than 4 bytes, each instance of the class will actually be larger than if it simply included the primitive directly, as it would in a non-static case)

3) Are the compilers smart enough to determine that in cases like the above, the variable is “effectively static” because it would be impossible to have different instances containing different values, and therefore optimize it like a finite static

Answer 1

1) How are final static primitives stored? Are they simply compiled directly into the expressions in which they are used?

Not compiled directly into expressions. They compile into a .class file and reference the ldc .

2) If they are actually reserved for storage, should each instance of the containing class maintain a reference to this location? (in this case, for primitives less than 4 bytes, each instance of the class will actually be larger than if it simply included the primitive directly, as it would in a non-static case)

No, the "link" is baked into bytecode, so nothing needs to be stored based on each instance.

3) Are the compilers smart enough to determine that in cases like the above, the variable is “effectively static” because it would be impossible to have different instances containing different values, and therefore optimize it like a finite static

Not sure, but I doubt it is optimized at the compiler level. JIT is likely to come into play. However, I'm not quite sure what "performance differences" you expect. No matter what happens, the performance impact will be negligible. (Static / non-static / final / non-final)