Java local variable

Question

This is a question about java local variables (Following code in the same method)

boolean userWantsToSave;
userWantsToSave = true;

Eclipse throws The value of the local variable userWantsToSave is not used, my question is why?

Since the variable is assigned true, why is it still not used?

Assigning a variable and never reading it is not using it. Eclipse is correct. — Boris the Spider
– Boris the Spider, Commented Nov 25, 2014 at 22:47
you'd have to use the variable if you wanted that to go away. like if(userWantsToSave){//doSomeCrazyStuff} — austin wernli
– austin wernli, Commented Nov 25, 2014 at 22:48
add a System.out.println(userWantsToSave); for example and the warning will disappear, i.e. use the variable, in this case just printing its value to the console. — A4L
– A4L, Commented Nov 25, 2014 at 22:49
Think of a variable as a parking space for a value of some kind. The assignment says what should be in the parking space. But even if you've got a car in your parking space, you haven't used it yet. — Dawood ibn Kareem
– Dawood ibn Kareem, Commented Nov 25, 2014 at 23:46

Salih Erikci · Accepted Answer · 2014-11-25 22:47:22Z

2

You assigned a value to it, but you never used the value of usertWantsToSave

if(usertWantsToSave){ // You read the value of usertWantsToSave. You used it
   save();
}

answered Nov 25, 2014 at 22:47

Salih Erikci

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mthandr · Accepted Answer · 2014-11-25 22:48:41Z

2

Just use it in a if (userWantsToSave) or something else. Using is reading the variable somewhere. Assigning a value is just that, it is not used because of that.

answered Nov 25, 2014 at 22:48

mthandr

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3 Comments

Thahleel al-Aleem Over a year ago

Why is if (userWantsToSave = true) not a use of the variable?

takendarkk Over a year ago

Because if you removed it the program would still be the same. That line makes no difference to the program at all.

A4L Over a year ago

@user2177940 userWantsToSave = true is assignment, use == to compaire.

Hanamant Guggari · Accepted Answer · 2017-06-23 14:16:30Z

1

Let me give you a real world example: lets say a parent x have two kids names a and b and x had got two sweets from market. Now x will give one sweet each to his/her kids. "This is just assignment" but both of these a and b have not eaten those sweets. "That's where it's not used"

answered Jun 23, 2017 at 14:16

Hanamant Guggari

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