In this Java 101 tutorial, I’ve explained how interfaces differ from classes, and showed you how to declare, implement, and extend interfaces in your Java programs.

Java’s interface language feature confuses many Java newbies. Many mistakenly assume that interfaces only sidestep Java’s failure to support multiple implementation inheritance. In reality ...

If you want to take advantage of sorting methods in Java, you'll need to implement the Comparable interface.

While languages like Ruby provide the pertinent information you need, why can't Java provide a decent, useable, toString() method right out of the box?