05-14 11:30:54.272 29119 18266 E AndroidRuntime: java.lang.NullPointerException: Attempt to invoke interface method 'int java.lang.Comparable.compareTo(java.lang.Object)' on a null object reference ...

An object that implements the Comparable interface must call the "implements" keyword first, and then the "compareTo" method must be defined in the Comparable class. This method can be defined in ...

If you want to take advantage of sorting methods in Java, you'll need to implement the Comparable interface. Written by David Petersheim, Contributor Feb. 17, 2005 at 8:00 a.m. PT ...

* Sorting an array of objects that implement Comparable is as simple as this: Arrays.sort(a); * By implementing Comparable, you allow your class to interoperate with all of the many generic algorithms ...

Now that we know what a natural order is, we need to look at how to specify it in Java. 5.2. Making a Class Comparable. In order to specify the natural ordering of an object, that object needs to be ...

The Person class now implements Comparable<Person>. This tells Java that a Person object can be compared to other Person objects. The new compareTo method should compare the current object (this) to ...