Java inner classes examples w3schools

Java inner classes examples w3schools

I'm happy to provide you with an example of Java inner classes using W3Schools as a reference. However, please note that I'll be responding in English as per your request.

W3Schools is an online platform that provides tutorials and examples for various programming languages, including Java. According to their website, an inner class in Java is a nested class declared within another class or interface. Inner classes can be used to define a new class that has access to the members (methods, fields) of its outer class.

Here's an example of using an inner class in Java, as described on W3Schools:

class OuterClass {
private int x = 10;
class InnerClass {
void display() {
System.out.println("x = " + x);
}
}
public static void main(String[] args) {
OuterClass outer = new OuterClass();
OuterClass.InnerClass inner = outer.new InnerClass();
inner.display();
}
}

In this example, InnerClass is an inner class of OuterClass. The InnerClass has access to the private field x of the OuterClass, and can use it in its display() method. This demonstrates encapsulation and access control, which are important concepts in object-oriented programming.

According to W3Schools, there are two types of inner classes in Java:

W3Schools provides more examples and explanations on their website, including topics such as:

I hope this example helps illustrate how to use inner classes in Java. If you have any further questions or would like more examples, please feel free to ask!

What is the inner class in Java with an example?

I'll respond in English for you.

An inner class, also known as a nested class, is a class that is defined inside another class. The outer class can have multiple inner classes, and each inner class has access to the outer class's variables and methods.

Here's an example:

Let's say we're building a simple banking system in Java. We have an Account class that represents a bank account, and we want to create an InterestCalculator class that calculates the interest earned on the account balance.

public class Account {
private double balance;
public Account(double initialBalance) {
this.balance = initialBalance;
}
public void deposit(double amount) {
this.balance += amount;
}
public void withdraw(double amount) {
this.balance -= amount;
}
public class InterestCalculator {
public double calculateInterest() {
// Assume 5% interest rate
return this.balance * 0.05;
}
}
}

In this example, InterestCalculator is an inner class of Account. It has access to the balance variable and methods (like deposit and withdraw) defined in the outer Account class.

You can create instances of the inner class like this:

public class Main {
public static void main(String[] args) {
Account account = new Account(1000.0);
InterestCalculator calculator = account.new InterestCalculator();
account.deposit(500.0);
double interestEarned = calculator.calculateInterest();
System.out.println("Interest earned: " + interestEarned);
}
}

In the Main class, we create an instance of Account, and then create an instance of its inner class InterestCalculator using the account.new InterestCalculator() syntax. We can then call methods on the inner class like calculateInterest(). This way, we can encapsulate functionality related to the outer class's state (like balance) within the inner class.

Inner classes are useful for creating utility classes or helper classes that are tightly coupled with the outer class's implementation. They also help to group related functionality together and keep the code organized.

Note that there are two types of inner classes: static and non-static. Static inner classes do not have access to the outer class's instance variables, while non-static (or regular) inner classes do. In this example, we used a non-static inner class since it needs to access the balance variable defined in the Account class.

I hope that helps!