Java: How to make this Serializable?

Question

I need the following class to be Serializable.

package helpers;

public class XY implements Comparable<XY>
{
    public int x;
    public int y;

    public XY (int x, int y)
    {
        this.x = x;
        this.y = y;
    }

    public int compareTo( XY other ) 
    {
        String compare1 = this.x + "-" + this.y;
        String compare2 = other.x + "-" + other.y;

        return compare1.compareTo( compare2 );
    }

    public String toString()
    {
        return this.x + "-" + this.y;
    }

}

As of now, I can't send it as an object with outputstream..I´ve tried to implement Serializable, but that didn't work.

Answer 1

Implementing Serializable will do the trick, but you must write the object with an ObjectOutputStream, not just an OutputStream.

Answer 2

You just need to inherit from java.io.Serializable:

public class XY implements Comparable<XY>, java.io.Serializable

Check more about serialization here.