Question

Are there any java.util.ExecutorService implementations which simply run all executed tasks in the calling thread? If this isn’t included in Java by default, is there a library which contains an implementation like this?

Answer 1

The only existing implementation I could find is SynchronousExecutorService – unfortunately buried somewhere in camel library.

Pasting source code (without comments) here for future reference:

package org.apache.camel.util.concurrent;

import java.util.List;
import java.util.concurrent.AbstractExecutorService;
import java.util.concurrent.TimeUnit;

public class SynchronousExecutorService extends AbstractExecutorService {

    private volatile boolean shutdown;

    public void shutdown() {
        shutdown = true;
    }

    public List<Runnable> shutdownNow() {
        return null;
    }

    public boolean isShutdown() {
        return shutdown;
    }

    public boolean isTerminated() {
        return shutdown;
    }

    public boolean awaitTermination(long time, TimeUnit unit) throws InterruptedException {
        return true;
    }

    public void execute(Runnable runnable) {
        runnable.run();
    }

}