Java 8 lambda expression example

Let’s discuss some more example of the lambda expression.

Example of Lambda expression with empty parameters

public interface Show 
{
	public void display();
}

public class ExampleWithoutParameters 
{
	public static void main(String[] args) 
	{
		Show show = () -> 
		{ 
			System.out.println("Not using any parameter");
			System.out.println("Provoding body to display() method");
		};
		show.display();
	}
}

Output: Not using any parameter
Providing body to display() method

Example of Lambda expression with parameters

public interface Show 
{
	public void display(int a, int b);
}

public class ExampleWithParameters 
{
	public static void main(String[] args) 
	{
		Show show = (int a, int b) -> 
		{ 
			System.out.println("Using two parameter value is:"+a+" "+b);
			System.out.println("Provoding body to display() method");
		};
		show.display(2,8);
	}
}

Output: Using two parameter value is:2 8
Provoding body to display() method

Example of Lambda expression with forEach

import java.util.ArrayList;

public class ExampleWithForEach
{
	public static void main(String[] args) 
	{
		ArrayList<String> list = new ArrayList<String>();
		list.add("Hi");
		list.add("Hello");
		list.add("Hey");
		list.add("Bye");
		list.add("Bye!!!!!");
		
		list.forEach(name -> System.out.println(name));
	}
}

Output: Hi
Hello
Hey
Bye
Bye!!!!!

Example with forEach for User-defined class

class Student 
{
	int rollNo;
	String className;
	String name;

	public Student(int rollNo, String className, String name) {
		this.rollNo = rollNo;
		this.className = className;
		this.name = name;
	}

	public int getRollNo() {
		return rollNo;
	}

	public void setRollNo(int rollNo) {
		this.rollNo = rollNo;
	}

	public String getClassName() {
		return className;
	}

	public void setClassName(String className) {
		this.className = className;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
}

import java.util.ArrayList;

public class ExampleWithForEach
{
	public static void main(String[] args) 
	{
		ArrayList<Student> list = new ArrayList<Student>();
		list.add(new Student(1, "MCA", "Ram"));
		list.add(new Student(2, "MSC", "Sham"));
		list.add(new Student(3, "BCA", "Krishan"));
		list.add(new Student(4, "CA", "Ravi"));
		list.add(new Student(5, "BBA", "Ram"));
		
		list.forEach(student -> System.out.println(student.getName()));	
	}
}

Output: Ram
Sham
Krishan
Ravi
Ram

Creating thread by using Lambda expression

class CreatingThreadByLambda
 {  
  public static void main(String args[])
  {  
    System.out.println("Thread id of Main thread is = "+ 
                Thread.currentThread().getId());
    Runnable runnable = () -> 
    {
    	System.out.println("Thread is running...");
        System.out.println("Thread id of new thread is="+Thread.currentThread().getId());
    };
    Thread thread = new Thread(runnable);
    thread.start();
   }  
}  

Output: Thread id of Main thread is = 1
Thread is running…
Thread id of new thread is=12