String constant vs variable in a Java method

Question

Unchangeable, constant values should be stored in constants rather than variables for both safer and cleaner code.

The latter doesn't apply to all cases of unchangeable values though: There's the following method that is only called once, on initialising the app that uses the same value of a String twice. The String is only referenced and used inside the method.

My question is: What's the best way of variable/constant definition? Being a simple String in a large application, performance and memory can be neglected, it's more about readability and maintenance.

Is it as variable inside the method:

protected void init() {
    final String thestring = "thevalue";

    methodA(thestring);
    methodB(thestring);
}

or is it as constant on class level (although only used in the method):

private static final String THESTRING = "thevalue";

protected void init() {

    methodA(THESTRING);
    methodB(THESTRING);
}

or a third, better solution? Please also take into consideration that there can be more, similar methods in the same class.

Answer 1

For me the best solution is to use variable inside the method - because it's internal variable. So other methods shouldn't see it. Consider the encapsulation and clean code, when you try to move this variable on class level you will get a long list of class variables.

Another thing is memory. After method is executed the variables are destroyed. When you define it as a static it will be in your memory all the time.