An interface is a collection of methods that must be implemented by the implementing class.
An interface defines a contract regarding what a class must do, without saying anything about how the class will do it.
Interface can contain declaration of methods and variables.
implementing class must define all the methods declared in the interface
If a class implements an interface and does not implement all the methods then class itself must be declared as abstract
Variables in interface automatically become static and final variableof the implementing class
Members of interface are implicitly public, so need not be declared as public.
An interface must be implemented in class.
yes we can define a variable in an interface in java.
Runnable interface
1.user defined packages 2.predefined packages
According to a beginner's book on Java, an interface can't have constructors. Also, the interface itself can't contain the method implementation.
Yes, it is possible to write a keylogger in Java, but you would need to use the Java Native Interface to do so.
yes we can define a variable in an interface in java.
NO, we cannot create a contructor for an interface in java.
No. It is a user defined function which the person who is creating the java class has to code by himself.
interface is a list of methods which implements that interface
A tagging interface type in Java is an interface that has not defined methods such as the java.io.Serializable interface.
Runnable interface
Yes. This is a valid interface definition in Java: interface Useless {}
An interface in Java is like an abstract class, but there are no method bodies allowed in it and it has to be declared with the interface keyword. It is Java's way of getting around the Deadly Diamond of Death. Only abstract methods and constants are allowed in it.
Interface is collection of abstract methods which has only declaration and no implementation
Interface Java can be used for a variety of tasks and commands such as .swf files, Java files, running scripts, as well as website video players for websites.
maybe
1.user defined packages 2.predefined packages