Thoughts: Avoid extending JFrame as it ties your GUI to being, well a JFrame. If instead you concentrate on creating JPanels instead, then you have the freedom to use these JPanels anywhere needed — in a JFrame, or JDialog, or JApplet, or inside of another JPanel, or swapped with other JPanels via a CardLayout. Avoid … Read more
No, there is no way to implement the same method in two different ways in one class in Java. That can lead to many confusing situations, which is why Java has disallowed it. interface ISomething { void doSomething(); } interface ISomething2 { void doSomething(); } class Impl implements ISomething, ISomething2 { void doSomething() {} // … Read more
They are absolutely different. Inheritance is an “is-a” relationship. Composition is a “has-a”. You do composition by having an instance of another class C as a field of your class, instead of extending C. A good example where composition would’ve been a lot better than inheritance is java.util.Stack, which currently extends java.util.Vector. This is now … Read more
For two objects, Foo and Bar the relationships can be defined Association – I have a relationship with an object. Foo uses Bar public class Foo { private Bar bar; }; NB: See Fowler’s definition – the key is that Bar is semantically related to Foo rather than just a dependency (like an int or … Read more
Prefer composition over inheritance?