How can I access to local variable from inner class method?

Question

I cannot access var variable from inner class method. but java is accessing to class variable instead of local variable. How can I access to local variable instead of class variable from inner class method ?

class Foo {
    void test() {
        int var = 3;

        class Inner {
            int var = 1;

            void print_var_of_test() {
                System.out.println(var); // this line prints 1 why ?
                // I want this line to print var of test (3) function.
            }
        }
    }
}

What happens if you give one of those variables a different name? — Joe C
– Joe C, Commented Oct 22, 2017 at 12:57
This isn't a case of a local variable and a class variable; it's an issue of two local variables. — Kevin Anderson
– Kevin Anderson, Commented Oct 22, 2017 at 13:21

davidxxx · Accepted Answer · 2017-10-22 13:16:02Z

2

You cannot access a local variable defined in a method of the outer class from an inner class if the inner class defines already a variable with the same name.
You could use distinct names to distinguish them.

As workaround to keep the same variable names, you could change the signature of print_var_of_test() to accept an int.
In this way, outside the inner class you could pass the int var variable as the method is invoked.

class Foo {

  void test() {
    int var = 3;

    class Inner {
        int var = 1;

        void print_var_of_test(int var) {
          System.out.println("outer var=" + var);
          System.out.println("inner var=" + this.var);
        }
    }

    Inner inner = new Inner();
    inner.print_var_of_test(var);
  }

}

edited Oct 22, 2017 at 13:16

answered Oct 22, 2017 at 12:52

davidxxx

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3 Comments

Nomad Over a year ago

is there a any other solution to solving this name problem ? because using different names is nonsense for me.

davidxxx Over a year ago

No you cannot. But as suggested by @mre you can use a workaround as changing the method to accept a parameter. I updated

Enrico Giurin Over a year ago

Can you please justify why you cannot access? Last but not least this is not an inner class, but a local nested class.

Erwin Bolwidt · Accepted Answer · 2017-10-22 12:58:46Z

1

You do that by picking another name for either the local variable or the inner class variable.

Since the inner class and the method variable are defined in the same source method, you should always be able to change one of them. There is never a situation in which you don't have the permission/right/capability to change one but not the other.

answered Oct 22, 2017 at 12:58

Erwin Bolwidt

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3 Comments

Nomad Over a year ago

can I solve this problem without using different names ? using different names (this way) doesn't make sense for me.

Erwin Bolwidt Over a year ago

@Nomad there isn't. The authors of the Java Language didn't think it was nonsense.

Enrico Giurin Over a year ago

What kind of answer is this? I can also do not use local nested classes, then what? Of course I can rename it, but this does not provide an answer to the original post.

Moamen Adel · Accepted Answer · 2017-10-22 13:08:53Z

0

What about naming inner class var as varInner if you want to compare between it and the original one?

answered Oct 22, 2017 at 13:08

Moamen Adel

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