Java accessing a string array in a method

It is not completly clear what you want to achieve but i will try to answer anyways. Option 1: You said you want to assign a variable in method a from method b in a nested class. That is not directly possible since function-variables are not accessible from another function and do no longer exist when the function has finished its execution. so you could transfer it as a input-parameter:

public class A {
    public void a(String[] input){
        String[] theArray = input;
    }

    private class B{
        private void b(){
            String[] input = new String[] {"an", "awesome", "Test"};
            a(input);
        }
    }
}

Option 2: Use a member-variable:

public class A {
    private String[] theArray;
    public void a(){
        this.theArray = new String[] {"a", "nice", "Test"};
        B bObject = new B();
        //modify value within b():
        bObject.b();

        //or assign it using a return value:
        this.theArray = bObject.b2();
    }

    private class B{
        private void b(){
            theArray = new String[] {"an", "awesome", "Test"};
        }

        private String[] b2(){
            return new String[] {"an", "awesome", "Test"};
        }
    }
}

Are you looking for something to show how Java passes by reference like the following:

public class Test {


    public Test() {

    }

    public void methodA() {
        String [] arr = new String[3];
        arr[0] = "One";
        arr[1] = "Two";
        arr[2] = "Three";
        printArray(arr);

        methodB(arr);

        printArray(arr);
    }

    public void methodB(String [] arr) {
        arr[0] = "A";
        arr[1] = "B";
        arr[2] = "C";
    }

    public void printArray(String [] arr) {
        for (int i = 0; i < 3; i++) {
            System.out.println(arr[i]);
        }
    }

    public static void main(String [] args) {
        Test test = new Test();
        test.methodA();
    }
}

This will output: One Two Three A B C