In this blog I explain you difference between callable and runnable interface with sample code.
| Runnable | Callable |
|---|---|
| Has run() method | Has call() method |
| The return type is void | The return type is Future |
| can run using Thread class | Can’t to run using Thread class |
| Can run using executor service. execute or submit method. ExecutorService service = Executors.newSingleThreadExecutor(); service.execute(runnableObj); service.submit(runnableObj); | Can run using executor service submit method only. ExecutorService service = Executors.newSingleThreadExecutor(); service.submit(callableObj); |
Sample Program
package com.samplecoder.threading;
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class RunnableVsCallable {
public static void main(String[] args) {
// TODO Auto-generated method stub
Runnable runnableObj = new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
System.out.println("Running runnable");
}
};
Callable<String> callableObj = new Callable<String>() {
@Override
public String call() throws Exception {
// TODO Auto-generated method stub
System.out.println("Running callable");
return null;
}
};
ExecutorService service = Executors.newSingleThreadExecutor();
service.execute(runnableObj);
service.submit(runnableObj);
service.submit(callableObj);
}
}
Result
Running runnable
Running runnable
Running callable
Conclusion
Now you should know the difference between the callable and runnable interface. And what it is. I believe, that you can write some basic program using callable and runnable interface.
