How to call a method with a separate thread in Java

Question

let s say I have a method doWork    How do I call it from a separate thread  not the main thread

User · Answer

If you are using at least Java 8 you can use method runAsync from class CompletableFuture

CompletableFuture.runAsync(() -> {...});

If you need to return a result use supplyAsync instead

CompletableFuture.supplyAsync(() -> 1);

User · Answer

In Java 8 you can do this with one line of code   If your method doesn t take any parameters  you can use a method reference   new Thread MyClass  doWork  start      Otherwise  you can call the method in a lambda expression   new Thread    - gt  doWork someParam   start

User · Answer

To achieve this with RxJava 2 x you can use   Completable fromAction this  dowork  subscribeOn Schedulers io   subscribe      The subscribeOn   method specifies which scheduler to run the action on - RxJava has several predefined schedulers  including Schedulers io   which has a thread pool intended for I O operations  and Schedulers computation   which is intended for CPU intensive operations

User · Answer

Sometime ago  I had written a simple utility class that uses JDK5 executor service and executes specific processes in the background  Since doWork   typically would have a void return value  you may want to use this utility class to execute it in the background   See this article where I had documented this utility

User · Answer

Create a class that implements the Runnable interface  Put the code you want to run in the run   method - that s the method that you must write to comply to the Runnable interface  In your  main  thread  create a new Thread class  passing the constructor an instance of your Runnable  then call start   on it  start tells the JVM to do the magic to create a new thread  and then call your run method in that new thread   public class MyRunnable implements Runnable        private int var       public MyRunnable int var            this var   var             public void run                code in the other thread  can reference  var  variable          public class MainThreadClass       public static void main String args              MyRunnable myRunnable   new MyRunnable 10           Thread t   new Thread myRunnable          t start                  Take a look at Java s concurrency tutorial to get started   If your method is going to be called frequently  then it may not be worth creating a new thread each time  as this is an expensive operation  It would probably be best to use a thread pool of some sort  Have a look at Future  Callable  Executor classes in the java util concurrent package

User · Answer

Another quicker option to call things  like DialogBoxes and MessageBoxes and creating separate threads for not-thread safe methods  would be to use the Lamba Expression     new Thread    - gt                           code here                 start

User · Answer

Thread t1   new Thread new Runnable          Override     public void run                code goes here              t1 start      or  new Thread new Runnable           Override      public void run                  code goes here            start      or  new Thread    - gt           code goes here     start      or  Executors newSingleThreadExecutor   execute new Runnable          Override     public void run             myCustomMethod                or   Executors newCachedThreadPool   execute new Runnable          Override     public void run             myCustomMethod

[java] How to call a method with a separate thread in Java?

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