micro optimization - Java - Declaring variables in for loops -

is declaring variable inside of loop poor practice? seem me doing so, seen in first code block below, use ten times memory second... due creating new string in each iteration of loop. correct?

for (int = 0; < 10; i++) {   string str = "some string"; } 

vs.

string str; (int = 0; < 10; i++) {   str = "some string"; } 

is declaring variable inside of loop poor practice?

not @ all! localizes variable point-of-use.

it seem me doing so, seen in first code block below, use ten times memory second

the compiler may optimize things keep memory use efficient. fyi: can it, if use final keyword tell variable has fixed reference object.

note: if have more complex object executing complex code in constructor, may need worry single vs. multiple executions, , declare object outside of loop.