What are inner class and anonymous class?

[chinmay]

Inner class : classes defined in other classes, including those defined in methods are called inner classes. An inner class can have any accessibility including private.

Anonymous class : Anonymous class is a class defined inside a method without a name and is instantiated and declared in the same place and cannot have explicit constructors.

[Shivangi Panwar]

Inner class is the class with in a class . It is treated like a member of the outer class and has access to all the members of the outer class even those which are declared as private . While An anonymous class is a local class without a name. An anonymous class is defined and instantiated in a single succinct expression using the new operator.

[calvinanag12]

Declaring Anonymous Classes


While local classes are class declarations, anonymous classes are expressions, which means that you define the class in another expression. The following example, HelloWorldAnonymousClasses, uses anonymous classes in the initialization statements of the local variables frenchGreeting and spanishGreeting, but uses a local class for the initialization of the variable englishGreeting:




public class HelloWorldAnonymousClasses {

interface HelloWorld {
public void greet();
public void greetSomeone(String someone);
}

public void sayHello() {

class EnglishGreeting implements HelloWorld {
String name = "world";
public void greet() {
greetSomeone("world");
}
public void greetSomeone(String someone) {
name = someone;
System.out.println("Hello " + name);
}
}

HelloWorld englishGreeting = new EnglishGreeting();

HelloWorld frenchGreeting = new HelloWorld() {
String name = "tout le monde";
public void greet() {
greetSomeone("tout le monde");
}
public void greetSomeone(String someone) {
name = someone;
System.out.println("Salut " + name);
}
};

HelloWorld spanishGreeting = new HelloWorld() {
String name = "mundo";
public void greet() {
greetSomeone("mundo");
}
public void greetSomeone(String someone) {
name = someone;
System.out.println("Hola, " + name);
}
};
englishGreeting.greet();
frenchGreeting.greetSomeone("Fred");
spanishGreeting.greet();
}


public static void main(String... args) {
HelloWorldAnonymousClasses myApp =
new HelloWorldAnonymousClasses();
myApp.sayHello();
}
}