Defining Abstract Classes

Q

How to define an Abstract class?

✍: FYIcenter

A

Defining an abstract class is done using the keyword "abstract". Here is an example of abstract class:

abstract class MyAbstract {
   protected String myString;
   public String getMyString() {
      return myString;
   }
   public abstract string getMyStringInYourWay();
}

2007-03-03, 5895👍, 0💬

Defining an Interface
How to define an Interface? Java Interface defines methods but does not implement them. Interface can include constants. A class that implements an interface is required to implement all the methods defined in the interface. Here is an example of interface definition: public interface MyInterface { ... 2007-03-03, 6160👍, 0💬

Differences between Interfaces and Abstract Classes
What's the difference between an interface and an abstract class? An abstract class may contain code in method bodies, which is not allowed in an interface. With abstract classes, you have to inherit your class from it and Java does not allow multiple inheritance. On the other hand, you can implemen... 2007-03-03, 6113👍, 0💬

Swing BorderLayout and Contrainer Classes
Name the containers which uses Border Layout as their default layout? Swing container classes which uses BorderLayout as their default are: Window, Frame and Dialog classes. 2007-03-03, 5983👍, 0💬

Serializable Interface
How many methods in the Serializable interface? There is no method in the Serializable interface. The Serializable interface acts as a marker, telling the object serialization tools that your class is serializable. 2007-03-03, 5943👍, 0💬

Externalizable Interface: readExternal() and readExternal()
How many methods in the Externalizable interface? There are two methods in the Externalizable interface. You have to implement these two methods in order to make your class externalizable. These two methods are readExternal() and readExternal(). 2007-03-03, 5913👍, 0💬

Defining Abstract Classes
How to define an Abstract class? Defining an abstract class is done using the keyword "abstract". Here is an example of abstract class: abstract class MyAbstract { protected String myString; public String getMyString() { return myString; } public abstract string getMyStringInYourWay(); } 2007-03-03, 5896👍, 0💬

Iterator Interface
Is Iterator a Class or Interface? What is its use? Iterator is an interface which is used to step through the elements of a Collection. 2007-03-03, 5887👍, 0💬

Serializalble and Externalizable Interfaces
What is the difference between Serializalble and Externalizable interface? When you use Serializable interface, your class is serialized automatically by default. But you can override writeObject() and readObject() two methods to control more complex object serailization process. When you use Extern... 2007-03-03, 5793👍, 0💬

What Is Synchronization
What do you understand by Synchronization? Synchronization is a process of controlling the access of shared resources by the multiple threads in such a manner that only one thread can access one resource at a time. In non synchronized multithreaded application, it is possible for one thread to modif... 2007-03-03, 5767👍, 0💬

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