关于禁止使用Executors创建线程池的分析

Factory and utility methods for Executor, ExecutorService, ScheduledExecutorService, ThreadFactory, and Callable classes defined in this package. This class supports the following kinds of methods:
Methods that create and return an ExecutorService set up with commonly useful configuration settings.
Methods that create and return a ScheduledExecutorService set up with commonly useful configuration settings.
Methods that create and return a "wrapped" ExecutorService, that disables reconfiguration by making implementation-specific methods inaccessible.
Methods that create and return a ThreadFactory that sets newly created threads to a known state.
Methods that create and return a Callable out of other closure-like forms, so they can be used in execution methods requiring Callable.

public static ExecutorService newFixedThreadPool(int nThreads)
Creates a thread pool that reuses a fixed number of threads operating off a shared unbounded queue. At any point, at most nThreads threads will be active processing tasks. If additional tasks are submitted when all threads are active, they will wait in the queue until a thread is available. If any thread terminates due to a failure during execution prior to shutdown, a new one will take its place if needed to execute subsequent tasks. The threads in the pool will exist until it is explicitly shutdown.

nThreads - the number of threads in the pool

the newly created thread pool

IllegalArgumentException - if nThreads <= 0

public static ExecutorService newFixedThreadPool(int nThreads,
                                                 ThreadFactory threadFactory)

public static ExecutorService newSingleThreadExecutor()
Creates an Executor that uses a single worker thread operating off an unbounded queue. (Note however that if this single thread terminates due to a failure during execution prior to shutdown, a new one will take its place if needed to execute subsequent tasks.) Tasks are guaranteed to execute sequentially, and no more than one task will be active at any given time. Unlike the otherwise equivalent newFixedThreadPool(1) the returned executor is guaranteed not to be reconfigurable to use additional threads.

the newly created single-threaded Executor

public static ExecutorService newSingleThreadExecutor(ThreadFactory threadFactory)

public static ExecutorService newCachedThreadPool()
Creates a thread pool that creates new threads as needed, but will reuse previously constructed threads when they are available. These pools will typically improve the performance of programs that execute many short-lived asynchronous tasks. Calls to execute will reuse previously constructed threads if available. If no existing thread is available, a new thread will be created and added to the pool. Threads that have not been used for sixty seconds are terminated and removed from the cache. Thus, a pool that remains idle for long enough will not consume any resources. Note that pools with similar properties but different details (for example, timeout parameters) may be created using ThreadPoolExecutor constructors.

the newly created thread pool

public static ExecutorService newCachedThreadPool(ThreadFactory threadFactory)

public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize)
Creates a thread pool that can schedule commands to run after a given delay, or to execute periodically.

corePoolSize - the number of threads to keep in the pool, even if they are idle

a newly created scheduled thread pool

IllegalArgumentException - if corePoolSize < 0

public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize,                                                ThreadFactory threadFactory)
                                                              
public static ScheduledExecutorService newSingleThreadScheduledExecutor()  

public static ScheduledExecutorService newSingleThreadScheduledExecutor(ThreadFactory threadFactory)

//-Xmx10m -Xms10m
public static void main(String[] args) throws InterruptedException{
		ThreadPoolExecutor threadPool = (ThreadPoolExecutor)Executors.newFixedThreadPool(1);

		IntStream.range(0,10000000).forEach((i)->{
				threadPool.execute(() -> {
					byte[] array = new byte[1024*1024*1];
					try {
						TimeUnit.HOURS.sleep(1);
						int length  = array.length;
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				});
		});

		threadPool.shutdown();
		threadPool.awaitTermination(1,TimeUnit.HOURS);
	}

Exception in thread "main" java.lang.OutOfMemoryError: GC overhead limit exceeded
	at java.util.concurrent.LinkedBlockingQueue.offer(LinkedBlockingQueue.java:416)
	at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1371)
	at com.dhb.executors.test.FixedThreadPoolOOM.lambda$main$1(FixedThreadPoolOOM.java:18)
	at com.dhb.executors.test.FixedThreadPoolOOM$$Lambda$1/1078694789.accept(Unknown Source)
	at java.util.stream.Streams$RangeIntSpliterator.forEachRemaining(Streams.java:110)
	at java.util.stream.IntPipeline$Head.forEach(IntPipeline.java:559)
	at com.dhb.executors.test.FixedThreadPoolOOM.main(FixedThreadPoolOOM.java:17)

//-Xmx10m -Xms10m
public static void main(String[] args) throws InterruptedException{
		ExecutorService threadPool =  Executors.newSingleThreadExecutor();

		IntStream.range(0,10000000).forEach((i)->{
			threadPool.execute(() -> {
				byte[] array = new byte[1024*1024*1];
				try {
					TimeUnit.HOURS.sleep(1);
					int length  = array.length;
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			});
		});

		threadPool.shutdown();
		threadPool.awaitTermination(1,TimeUnit.HOURS);
	}

Exception in thread "main" java.lang.OutOfMemoryError: GC overhead limit exceeded
	at java.util.concurrent.LinkedBlockingQueue.offer(LinkedBlockingQueue.java:416)
	at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1371)
	at java.util.concurrent.Executors$DelegatedExecutorService.execute(Executors.java:668)
	at com.dhb.executors.test.SingleThreadOOM.lambda$main$1(SingleThreadOOM.java:15)
	at com.dhb.executors.test.SingleThreadOOM$$Lambda$1/1078694789.accept(Unknown Source)
	at java.util.stream.Streams$RangeIntSpliterator.forEachRemaining(Streams.java:110)
	at java.util.stream.IntPipeline$Head.forEach(IntPipeline.java:559)
	at com.dhb.executors.test.SingleThreadOOM.main(SingleThreadOOM.java:14)

//-Xms10m -Xmx10m
public static void main(String[] args) throws InterruptedException{
		ExecutorService threadPool =  Executors.newCachedThreadPool();

		IntStream.range(0,10000000).forEach((i)->{
			threadPool.execute(() -> {
				byte[] array = new byte[1024*1024*1];
				try {
					TimeUnit.HOURS.sleep(1);
					int length  = array.length;
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
			});
		});

		threadPool.shutdown();
		threadPool.awaitTermination(1,TimeUnit.HOURS);
	}

java.lang.OutOfMemoryError: Java heap space
java.lang.OutOfMemoryError: Java heap space
java.lang.OutOfMemoryError: Java heap space
java.lang.OutOfMemoryError: Java heap space
	at com.dhb.executors.test.CachedThreadPoolOOM.lambda$null$0(CachedThreadPoolOOM.java:16)
	at com.dhb.executors.test.CachedThreadPoolOOM$$Lambda$2/1149319664.run(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
java.lang.OutOfMemoryError: Java heap space

public static void main(String[] args) {
		ExecutorService threadPool =  Executors.newScheduledThreadPool(1);

		try {
			IntStream.range(0,10000000).forEach((i)->{
				threadPool.execute(() -> {
					byte[] array = new byte[1024*1024*1];
					try {
						TimeUnit.HOURS.sleep(1);
						int length  = array.length;
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				});
			});

			threadPool.shutdown();
			threadPool.awaitTermination(1,TimeUnit.HOURS);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}

Exception in thread "main" java.lang.OutOfMemoryError: GC overhead limit exceeded
	at java.util.concurrent.Executors.callable(Executors.java:407)
	at java.util.concurrent.FutureTask.<init>(FutureTask.java:152)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.<init>(ScheduledThreadPoolExecutor.java:209)
	at java.util.concurrent.ScheduledThreadPoolExecutor.schedule(ScheduledThreadPoolExecutor.java:532)
	at java.util.concurrent.ScheduledThreadPoolExecutor.execute(ScheduledThreadPoolExecutor.java:622)
	at com.dhb.executors.test.ScheduledThreadPoolOOM.lambda$main$1(ScheduledThreadPoolOOM.java:15)

    public static ExecutorService newFixedThreadPool(int nThreads) {
        return new ThreadPoolExecutor(nThreads, nThreads,
                                      0L, TimeUnit.MILLISECONDS,
                                      new LinkedBlockingQueue<Runnable>());
    }

 public static ExecutorService newSingleThreadExecutor() {
        return new FinalizableDelegatedExecutorService
            (new ThreadPoolExecutor(1, 1,
                                    0L, TimeUnit.MILLISECONDS,
                                    new LinkedBlockingQueue<Runnable>()));
    }

  public static ExecutorService newCachedThreadPool() {
        return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
                                      60L, TimeUnit.SECONDS,
                                      new SynchronousQueue<Runnable>());
    }

    public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize) {
        return new ScheduledThreadPoolExecutor(corePoolSize);
    }
    
       public ScheduledThreadPoolExecutor(int corePoolSize) {
        super(corePoolSize, Integer.MAX_VALUE, 0, NANOSECONDS,
              new DelayedWorkQueue());
    }

 public LinkedBlockingQueue() {
        this(Integer.MAX_VALUE);
    }

private static ExecutorService executor = new ThreadPoolExecutor(10, 10,
60L, TimeUnit.SECONDS,
new ArrayBlockingQueue(10));

private static ThreadFactory namedThreadFactory = new ThreadFactoryBuilder()
.setNameFormat("test-pool-%d").build();
private static ExecutorService pool = new ThreadPoolExecutor(5, 20,
0L, TimeUnit.MILLISECONDS,
new LinkedBlockingQueue<Runnable>(100), namedThreadFactory, new
ThreadPoolExecutor.
AbortPolicy());