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Sep 11, 2012 · For example, the standard Java class java.util.LinkedHashSet extends java.util.HashSet. The method add() is overridden in LinkedHashSet. If you have a variable that is of type HashSet, and you call its add() method, it will call the appropriate implementation of add(), based on whether it is a HashSet or a LinkedHashSet. This is called ...
This way the new method masks the parent method and would get invoked by default. class Thought { public void message() { System.out.println("I feel like I am diagonally parked in a parallel universe."); } } public class Advice extends Thought { @Override // @Override annotation in Java 5 is optional but helpful.
May 15, 2012 · Based on my recent Java studies . method overriding, when the subclass have the same method with the same signature in the subclass. Method hiding, when the subclass have the same method name, but different parameter. In this case, you're not overriding the parent method, but hiding it. Example from OCP Java 7 book, page 70-71:
Feb 4, 2013 · Java supports * covariant return types when overriding methods. An overriding method may have a more specific return type than the method being overridden. That is, as long as the new method's return type is assignable to the return type of the method it overrides, it's allowed. For example: class ShapeBuilder { ...
Jan 25, 2013 · Convariant return types were added in Java 5.0 I wouldn't worry about anything pre Java 6 too much. There was a bug in Java 6 which allowed to to overload the return type, but this has been fixed in Java 7 ;) –
Oct 9, 2009 · First and most important rule regarding method overriding in Java is that you can only override method in sub class. You can not override method in same class. Second important rule of method overriding in Java that name and signature of method must be same in Super class and Sub class or in interface and its implementation.
Oct 1, 2008 · Method overloading means writing two or more methods in the same class by using same method name, but the passing parameters is different. Method overriding means we use the method names in the different classes,that means parent class method is used in the child class. In Java to achieve polymorphism a super class reference variable can hold ...
Item 10: Obey the general contract when overriding equals. According to Effective Java, Overriding the equals method seems simple, but there are many ways to get it wrong, and consequences can be dire. The easiest way to avoid problems is not to override the equals method, in which case each instance of the class is equal only to itself. This ...
May 24, 2012 · The toString() method returns the string representation of the object. If you print any object, java compiler internally invokes the toString() method on the object. So overriding the toString() method, returns the desired output, it can be the state of an object etc. depends on your implementation. Advantage of Java toString() method
Oct 12, 2016 · Rules for hiding a method are the same rules for overriding with addtion of static keyword. With static keyword, you are hiding display() method. So when obj calls method show() , computer goes like this: I have object Child with Parent reference(it can be Child reference and output will still be the same in this example).
