Difference between Runnable and Callable interface in java
Runnable and Callable both functional interface. Classes which are implementing these interfaces are designed to be executed by another thread.
Thread can be started with Ruunable and they are two ways to start a new thread: one is by subclassing Thread class and another is implementing Runnable interface.
Thread class does not have constructor for callable so we should use ExecutorService class for executing thread.
| Sr. No. | Key | Runnable | Callable |
|---|
1
| Package
| It belongs to Java.lang
| It belongs to java.util.concurrent
|
2
| Thread Creation
| We can create thread by passing runnable as a parameter.
| We can’t create thread by passing callable as parameter
|
3
| Return Type
| Ruunable does not return anything
| Callable can return results
|
4.
| Method
| It has run() method
| It has call()method
|
5
| Bulk Execution
| It can’t be used for bulk execution of task
| It can be used for bulk execution of task by invoking invokeAll().
|
Example of Runnable
public class RunnableExample implements Runnable {
public void run() {
System.out.println("Hello from a Runnable!");
}
public static void main(String args[]) {
(new Thread(new RunnableExample())).start();
}
}Example of Callable
public class Main {
public static void main(String args[]) throws InterruptedException, ExecutionException {
ExecutorService services = Executors.newSingleThreadExecutor();
Future<?> future = services.submit(new Task());
System.out.println("In Future Object" + future.get());
}
}
import java.util.concurrent.Callable;
public class Task implements Callable {
@Override
public String call() throws Exception {
System.out.println("In call");
String name = "test";
return name;
}
}
Published on 09-Sep-2020 13:02:18
