My name
is
Jon Skeet

Why do I need to transform variable into final array inside @Override[inner class] method?

I'm using following code :

 public void addConditions(){
    final String arriveHourse, departHourse, arriveMinutes, departMinutes;
    TimePickerDialog.OnTimeSetListener departOnTimeSetListener = new TimePickerDialog.OnTimeSetListener() {
        @Override
        public void onTimeSet(TimePicker timePicker, int selectedHours, int selectedMinutes) {

            departHourse = String.valueOf(selectedHours);
            departMinutes = String.valueOf(selectedMinutes);

        }
    };

...
}

Why the IDE asked me to transform departHourse into final array ?

Why this happened, and how i can avoid that ?

Also if i moved variable outside class, it's work like :

String arriveHourse, departHourse, arriveMinutes, departMinutes;

public void addConditions(){

    TimePickerDialog.OnTimeSetListener departOnTimeSetListener = new TimePickerDialog.OnTimeSetListener() {
        @Override
        public void onTimeSet(TimePicker timePicker, int selectedHours, int selectedMinutes) {

            departHourse = String.valueOf(selectedHours);
            departMinutes = String.valueOf(selectedMinutes);

        }
    };

...
}

departHourse is a final variable. It has to be, in order to be used within the anonymous inner class. That means you can't assign a new value to it in the anonymous inner class.

One way around that is to create a single-element array instead:

final String[] valueHolder = new String[1];
...
Foo foo = new Foo() {
    @Override public void bar() {
        valueHolder[0] = "Set in bar";
    }
}

An alternative is to use AtomicReference:

final AtomicReference<String> valueHolder = new AtomicReference<String>();
...
Foo foo = new Foo() {
    @Override public void bar() {
        valueHolder.set("Set in bar");
    }
}

In both cases, this allows you to make new information available without changing the value of the valueHolder variable itself.

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