Your run method takes a Runnable instance, and that explains why run(new R()) works with the R implementation. R::new is not equivalent to new R(). It can fit the signature of a Supplier<Runnable> (or similar functional interfaces), but R::new cannot be used as a Runnable implemented with your R class. A version of your run … Read more
Use Callable<V> instead of using Runnable interface. Example: public static void main(String args[]) throws Exception { ExecutorService pool = Executors.newFixedThreadPool(3); Set<Future<Integer>> set = new HashSet<>(); for (String word : args) { Callable<Integer> callable = new WordLengthCallable(word); Future<Integer> future = pool.submit(callable); set.add(future); } int sum = 0; for (Future<Integer> future : set) { sum += future.get(); … Read more
For Runnable interface you should have something like that: Runnable runnable = () -> {}; Where: () because run method doesn’t receive args {} body of run method which in this case is empty After that, you can call the method runnable.run();
Using Java 8: map.replaceAll((k, v) -> v – 20); Using Java 7 or older: You can iterate over the entries and update the values as follows: for (Map.Entry<Key, Long> entry : playerCooldowns.entrySet()) { entry.setValue(entry.getValue() – 20); }
Just use the removeCallbacks(Runnable r) method.
You can use a Callable instead, submitting it to an ExecutorService and waiting for result with FutureTask.isDone() returned by the ExecutorService.submit(). When isDone() returns true you call FutureTask.get(). Now, if your Callable has thrown an Exception then FutureTask.get() wiill throw an Exception too and the original Exception you will be able to access using Exception.getCause().
A Runnable is basically a type of class (Runnable is an Interface) that can be put into a thread, describing what the thread is supposed to do. The Runnable Interface requires of the class to implement the method run() like so: public class MyRunnableTask implements Runnable { public void run() { // do stuff here … Read more
Well it’s been almost 9 years since I originally posted this and to be honest, Java has made a couple improvements since then. I’ll leave my original answer below, but there’s no need for people to do what is in it. 9 years ago, during code review I would have questioned why they did it … Read more
First example: No multiple threads. Both execute in single (existing) thread. No thread creation. R1 r1 = new R1(); R2 r2 = new R2(); r1 and r2 are just two different objects of classes that implement the Runnable interface and thus implement the run() method. When you call r1.run() you are executing it in the … Read more
Guava almost always has what you need. ThreadFactory namedThreadFactory = new ThreadFactoryBuilder().setNameFormat(“my-sad-thread-%d”).build() and pass it off to your ExecutorService.