How to use a private method in Java

I am given a class that has a private method say setCoors(int x, int y). The constructor of that class has the setCoors in it too. In a different class, I want to have a method setLocation which calls setCoors. Is this possible?

New Question:

If I am not allowed to set the method to public, is this possible?

public class Coordinate{
    public Coordinate(int a, int b){
        se开发者_如何转开发tCoors(a,b)
    }
    private void setCoords(int x, int y)
}

public class Location{
    private Coordinate  loc;
    public void setLocation(int a, int b)
        loc = new Coordinate(a,b)
}

The best and most helpful answer depends on the context of the question, which is, I believe, not completely obvious.

If the question was a novice question about the intended meaning of private, then the answer "no" is completely appropriate. That is:

• private members of A are accessible only within class A
• package-private members of A are accessible only within classes in A's package
• protected members of A are accessible only within classes in A's package and subclasses of A
• public members of A are accessible anywhere A is visible.

Now, if, and okay maybe this is a stretch (thank you Brian :) ), that the question came from a more "advanced" context where one is looking at the question of "I know private means private but is there a language loophole", then, well, there is such a loophole. It goes like this:

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.List;

class C {
    private int x = 10;
    private void hello() {System.out.println("Well hello there");}
}

public class PrivateAccessDemo {
    public static void main(String[] args) throws Exception {
        C c = new C();
        List<Field> fields = Arrays.asList(C.class.getDeclaredFields());
        for (Field f: fields) {
            f.setAccessible(true);
            System.out.println(f.getName() + " = " + f.get(c));
        }
        List<Method> methods = Arrays.asList(C.class.getDeclaredMethods());
        for (Method m: methods) {
            m.setAccessible(true);
            m.invoke(c);
        }
    }
}

Output:

x = 10
Well hello there

Of course, this really isn't something that application programmers would ever do. But the fact that such a thing can be done is worthwhile to know, and not something that should be ignored. IMHO anyway.

No, private means the method can only be called inside of the Class in which it is defined. You will probably want to have setLocation create a new instance of the class setCoords resides in, or change the visibility on setCoords.

EDIT: The code you have posted will work. Just be aware that any instance of the Location class will be bound to its own Coordinate object. If you create a new Coordinate object somewhere else in your code, you will be unable to modify its internal state. In other words, the line

Coordinate myCoord = new Coordinate(4, 5);

will create the object myCoord which will forever have the coordinates 4 and 5.

private means it's private

If you want other classes to call it, maybe you shouldn't make it private?

No private methods can't be accessed outside the class in which they are defined

Kid-doing-homework: the answer is no. Guy-requiring-some-crazy-work-around-for-his-job: the answer is yes. Far more importantly though, Your setCoors method should not take int arguments. It should take two SilverBullet objects.

private means you can only access it inside the class defined.