Inner Class In Java

-

In Java, an inner class is a class that is defined inside another class. Inner classes are useful when you want to encapsulate one class inside another class, so that the inner class has access to the private members of the outer class.

There are four types of inner classes in Java:

  1. Member inner class: A member inner class is defined at the member level of a class. It can access all members of the enclosing class, including private members.

  2. Static inner class: A static inner class is a nested class that is declared as static. It can access only static members of the enclosing class.

  3. Local inner class: A local inner class is defined inside a method or a block of code. It has access to the final local variables of the enclosing method or block.

  4. Anonymous inner class: An anonymous inner class is a local inner class without a name. It is typically used for creating a single object of an interface or an abstract class.

Here's an example of a member inner class:

code with mohit
public class OuterClass {
    private int x = 10;

    public class InnerClass {
        public void printX() {
            System.out.println(x);
        }
    }
}

In this example, InnerClass is a member inner class of OuterClass. It has access to the private member x of OuterClass.

To create an instance of the inner class, you first need to create an instance of the outer class, like this:

code with mohit
OuterClass outer = new OuterClass();
OuterClass.InnerClass inner = outer.new InnerClass();
inner.printX(); // prints 10

Comments

Post a Comment

Popular posts from this blog

Cryptography API

-
Java offers a comprehensive set of cryptographic functionalities through its `java.security` package. This package provides various classes and interfaces for encryption, decryption, key generation, digital signatures, and more. Here are some key classes and concepts within Java's Cryptography API: 1. **Message Digests (Hashing):** Classes like `MessageDigest` help generate hash values for data using algorithms like MD5, SHA-1, SHA-256, etc. 2. **Encryption/Decryption:** The `Cipher` class allows encryption and decryption using various algorithms like AES, DES, RSA, etc. 3. **Key Management:** Java provides classes such as `KeyGenerator` for generating symmetric keys, `KeyPairGenerator` for key pairs (for asymmetric encryption), and `KeyStore` for managing keys and certificates. 4. **Digital Signatures:** The `Signature` class helps create and verify digital signatures. Here's a simple example demonstrating encryption and decryption using Java's Cryptography API: ```java im...
Read more

Java Applet Overview

-
  An applet in Java is a special type of program that is designed to be executed within a web browser. Applets are written in the Java programming language and can be embedded within an HTML page using the <applet> tag. When the HTML page containing the applet is loaded in a web browser, the applet code is downloaded and executed by the Java Virtual Machine (JVM) built into the browser. Applets are often used to provide interactive functionality on a web page, such as games, animations, and data visualization. They have access to a limited set of features and resources provided by the web browser, such as user input events and graphics libraries, but are restricted from accessing resources on the user's computer or network. In recent years, the use of applets has declined in favor of other technologies such as JavaScript, HTML5, and CSS. However, applets are still supported by some web browsers and can be a useful tool in certain situations where other technologies may not be...
Read more

Vector in Java

-
  In Java, a vector is a resizable collection of objects, similar to an array, but with some additional functionality. A vector can grow or shrink dynamically, and can be accessed using an index just like an array. To use a vector in Java, you first need to import the java.util.Vector package. Then you can create a new vector object using the following syntax: java Copy code Vector<Object> vectorName = new Vector <Object>(); Here, Object can be replaced with any data type that you want to store in the vector. For example, if you want to store integers, you can use: java Copy code Vector<Integer> intVector = new Vector <Integer>(); To add elements to the vector, you can use the add() method: java Copy code intVector.add( 1 ); intVector.add( 2 ); intVector.add( 3 ); To access an element in the vector, you can use the get() method: java Copy code int element = intVector.get( 0 ); // returns the first element (1) You can also use other methods provided...
Read more