Java class keyword

A Java class keyword is the most common keyword which is used to declare a new Java class. A class is a container that contains the block of code that includes field, method, constructor, etc.

A class is a template or blueprint from which objects are created. It is a logical entity. It can't be physical.

Points to remember

Every object is an instance of a class.
A class can contain one or more classes. This concept can be called a nested class.
We can assign only public, abstract, strictfp and final modifier to class. However, we can assign other modifiers like private, protected and static to the inner java class.
A class name must be unique within a package.
We can use a class keyword as Class.class to get a Class object without needing an instance of that class.

Example 1

Let's see a simple example of a class keyword.

public class ClassExample {

	public static void main(String[] args) {
		
		System.out.println("Hello World");
	}
	
}

Output:

Hello World

Example 2

In this example, we declare two classes.

class Employee
{
	int id;
	String name;
	long salary;
	public Employee(int id, String name, long salary) {
		super();
		this.id = id;
		this.name = name;
		this.salary = salary;
	}

}

class ClassExample
{

	public static void main(String[] args) {
		
		Employee e=new Employee(101,"John William",25000);

	System.out.println(e.id+" "+e.name+" "+e.salary);
	
		
	}
}

Output:

101 John William 25000

Example 3

Let's see an example to declare the private class.

class ClassExample{  
String msg="private class is invoked";  
 
 private class Inner
 {  
  void display()
  {
	  System.out.println(msg);
	  
  }  
 }  
 public static void main(String args[]){  
	 ClassExample obj=new ClassExample();  
	 ClassExample.Inner in=obj.new Inner();  
      in.display();  
 }  
} 

Output: