Runnable import java class

Java 8 Runnable and Callable Lambda Example with Argument

On this page we will provide Java 8 Runnable and Callable lambda example with argument. In java 8 Runnable and Callable both interface have been annotated by @FunctionalInterface . We can implement run() and call() method using lambda expression. Here on this page we will also provide how to pass arguments to Runnable and Callable methods.

Java 8 Runnable Lambda Example with Argument

Java 8 supports lambda expression. In java 8 Runnable interface has been annotated with @FunctionalInterface . Now we can create Runnable instance using lambda expression.

Runnable r = () -> System.out.println("Hello World!"); Thread th = new Thread(r); th.start();

Runnable r = new Runnable() < @Override public void run() < System.out.println("Hello World!"); >>; Thread th = new Thread(r); th.start();

In case we need to write more than one line of code inside run() method, we can do using lambda expression as given below.

Now find the complete example of Java 8 Runnable with lambda expression using Thread class.
Java8RunnableDemo.java

package com.concretepage.runnable; import java.util.Arrays; import java.util.List; import java.util.function.Consumer; import com.concretepage.Book; public class Java8RunnableDemo < public static void main(String[] args) < final List&ltBook&gt list = Arrays.asList(new Book(1, "Ramayan"), new Book(2, "Mahabharat")); Runnable r1 = () -&gt list.forEach(Book::print); Thread th1 = new Thread(r1); th1.start(); Runnable r2 = () -&gt < Consumer&ltBook&gt style = (Book b) -&gt System.out.println("Book Id:"+b.getId() + ", Book Name:"+b.getName()); list.forEach(style); >; Thread th2 = new Thread(r2); th2.start(); > >

package com.concretepage; public class Book < public int id; public String name; public Book(int id, String name)< this.id = id; this.name = name; >public int getId() < return id; >public void setId(int id) < this.id = id; >public String getName() < return name; >public void setName(String name) < this.name = name; >public void print() < System.out.println("id:"+id + ", Name:"+name); >>

id:1, Name:Ramayan Book Id:1, Book Name:Ramayan id:2, Name:Mahabharat Book Id:2, Book Name:Mahabharat

Find the sample code to run the Runnable instance using ExecutorService .
Java8RunnableDemoExecutor.java

package com.concretepage.runnable; import java.util.Arrays; import java.util.List; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.function.Consumer; import com.concretepage.Book; public class Java8RunnableDemoExecutor < public static void main(String[] args) < final List&ltBook&gt list = Arrays.asList(new Book(1, "Ramayan"), new Book(2, "Mahabharat")); ExecutorService service = Executors.newFixedThreadPool(2); Runnable r1 = () -&gt list.forEach(Book::print); service.execute(r1); Runnable r2 = () -&gt < Consumer&ltBook&gt style = (Book b) -&gt System.out.println("Book Id:"+b.getId() + ", Book Name:"+b.getName()); list.forEach(style); >; service.execute(r2); > >

id:1, Name:Ramayan id:2, Name:Mahabharat Book Id:1, Book Name:Ramayan Book Id:2, Book Name:Mahabharat

Java 8 Callable Lambda Example with Argument

Callable&ltV&gt interface has been introduced in Java 5 where V is a return type. In Java 8, Callable interface has been annotated with @FunctionalInterface . Now in java 8, we can create the object of Callable using lambda expression as follows.

final int val = 10; Callable<Integer> callableObj = () -> < return 2*val; >;

Now find the complete example of Callable with lambda expression using ExecutorService .
Java8CallableDemo.java

package com.concretepage.callable; import java.util.Arrays; import java.util.List; import java.util.concurrent.Callable; import java.util.concurrent.ExecutionException; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.Future; public class Java8CallableDemo < public static void main(String[] args) < final List&ltInteger&gt integers = Arrays.asList(1,2,3,4,5); Callable&ltInteger&gt callableObj = () -&gt < int result = integers.stream().mapToInt(i -&gt i.intValue()).sum(); return result; >; ExecutorService service = Executors.newSingleThreadExecutor(); Future<Integer> future = service.submit(callableObj); Integer result=0; try < result = future.get(); >catch (InterruptedException e) < e.printStackTrace(); >catch (ExecutionException e) < e.printStackTrace(); >System.out.println("Sum preBg"> 
Sum = 15
 
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