本文整理了Java中java.lang.System.gc()方法的一些代码示例，展示了System.gc()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。System.gc()方法的具体详情如下：
包路径：java.lang.System
类名称：System
方法名：gc

System.gc介绍

[英]Indicates to the VM that it would be a good time to run the garbage collector. Note that this is a hint only. There is no guarantee that the garbage collector will actually be run.
[中]向VM指示运行垃圾回收器的最佳时机。请注意，这只是一个提示。不能保证垃圾收集器将实际运行。

代码示例

代码示例来源：origin: ReactiveX/RxJava

@Override
  public void accept(byte[] v) throws Exception {
    System.out.println("Bounded Replay Leak check: Wait before GC 2");
    Thread.sleep(1000);
    System.out.println("Bounded Replay Leak check:  GC 2");
    System.gc();
    Thread.sleep(500);
    after.set(memoryMXBean.getHeapMemoryUsage().getUsed());
  }
});

代码示例来源：origin: ReactiveX/RxJava

@Override
  public void accept(byte[] v) throws Exception {
    System.out.println("Bounded Replay Leak check: Wait before GC 2");
    Thread.sleep(1000);
    System.out.println("Bounded Replay Leak check:  GC 2");
    System.gc();
    Thread.sleep(500);
    after.set(memoryMXBean.getHeapMemoryUsage().getUsed());
  }
});

代码示例来源：origin: ReactiveX/RxJava

@Override
  public void accept(byte[] v) throws Exception {
    System.out.println("Bounded Replay Leak check: Wait before GC 2");
    Thread.sleep(1000);
    System.out.println("Bounded Replay Leak check:  GC 2");
    System.gc();
    Thread.sleep(500);
    after.set(memoryMXBean.getHeapMemoryUsage().getUsed());
  }
});

代码示例来源：origin: ReactiveX/RxJava

@Override
  public void accept(byte[] v) throws Exception {
    System.out.println("Bounded Replay Leak check: Wait before GC 2");
    Thread.sleep(1000);
    System.out.println("Bounded Replay Leak check:  GC 2");
    System.gc();
    Thread.sleep(500);
    after.set(memoryMXBean.getHeapMemoryUsage().getUsed());
  }
});

代码示例来源：origin: bumptech/glide

void tearDown() {
  // GC before delete() to release files on Windows (https://stackoverflow.com/a/4213208/253468)
  System.gc();
  if (file.exists() && !file.delete()) {
   throw new IllegalStateException("Failed to delete: " + file);
  }
 }
}

代码示例来源：origin: bumptech/glide

@After
public void tearDown() {
 // GC before delete() to release files on Windows (https://stackoverflow.com/a/4213208/253468)
 System.gc();
 if (!file.delete()) {
  throw new IllegalStateException("Failed to delete: " + file);
 }
}

代码示例来源：origin: bumptech/glide

@After
public void tearDown() {
 // GC before delete() to release files on Windows (https://stackoverflow.com/a/4213208/253468)
 System.gc();
 if (file.exists() && !file.delete()) {
  throw new RuntimeException("Failed to delete file");
 }
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void replayNoLeak() throws Exception {
  System.gc();
  Thread.sleep(100);
  long start = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed();
  source = Observable.fromCallable(new Callable<Object>() {
    @Override
    public Object call() throws Exception {
      return new byte[100 * 1000 * 1000];
    }
  })
  .replay(1)
  .refCount();
  source.subscribe();
  System.gc();
  Thread.sleep(100);
  long after = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed();
  source = null;
  assertTrue(String.format("%,3d -> %,3d%n", start, after), start + 20 * 1000 * 1000 > after);
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void replayNoLeak() throws Exception {
  System.gc();
  Thread.sleep(100);
  long start = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed();
  source = Flowable.fromCallable(new Callable<Object>() {
    @Override
    public Object call() throws Exception {
      return new byte[100 * 1000 * 1000];
    }
  })
  .replay(1)
  .refCount();
  source.subscribe();
  System.gc();
  Thread.sleep(100);
  long after = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed();
  source = null;
  assertTrue(String.format("%,3d -> %,3d%n", start, after), start + 20 * 1000 * 1000 > after);
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void publishNoLeak() throws Exception {
  System.gc();
  Thread.sleep(100);
  long start = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed();
  source = Flowable.fromCallable(new Callable<Object>() {
    @Override
    public Object call() throws Exception {
      throw new ExceptionData(new byte[100 * 1000 * 1000]);
    }
  })
  .publish()
  .refCount();
  source.subscribe(Functions.emptyConsumer(), Functions.emptyConsumer());
  System.gc();
  Thread.sleep(100);
  long after = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage().getUsed();
  source = null;
  assertTrue(String.format("%,3d -> %,3d%n", start, after), start + 20 * 1000 * 1000 > after);
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void justUnsubscribed() throws Exception {
  o = new Object();
  WeakReference<Object> wr = new WeakReference<Object>(o);
  TestObserver<Long> to = Observable.just(o).count().toObservable().onTerminateDetach().test();
  o = null;
  to.cancel();
  System.gc();
  Thread.sleep(200);
  Assert.assertNull("Object retained!", wr.get());
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void just() throws Exception {
  o = new Object();
  WeakReference<Object> wr = new WeakReference<Object>(o);
  TestObserver<Object> to = new TestObserver<Object>();
  Observable.just(o).count().toObservable().onTerminateDetach().subscribe(to);
  to.assertValue(1L);
  to.assertComplete();
  to.assertNoErrors();
  o = null;
  System.gc();
  Thread.sleep(200);
  Assert.assertNull("Object retained!", wr.get());
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void justUnsubscribed() throws Exception {
  o = new Object();
  WeakReference<Object> wr = new WeakReference<Object>(o);
  TestSubscriber<Object> ts = new TestSubscriber<Object>(0);
  Flowable.just(o).count().toFlowable().onTerminateDetach().subscribe(ts);
  ts.cancel();
  o = null;
  System.gc();
  Thread.sleep(200);
  Assert.assertNull("Object retained!", wr.get());
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void completeDetaches() throws Exception {
  Disposable d = Disposables.empty();
  final WeakReference<Disposable> wr = new WeakReference<Disposable>(d);
  TestObserver<Void> to = new Completable() {
    @Override
    protected void subscribeActual(CompletableObserver observer) {
      observer.onSubscribe(wr.get());
      observer.onComplete();
      observer.onComplete();
    };
  }
  .onTerminateDetach()
  .test();
  d = null;
  System.gc();
  Thread.sleep(200);
  to.assertResult();
  assertNull(wr.get());
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void cancelDetaches() throws Exception {
  Disposable d = Disposables.empty();
  final WeakReference<Disposable> wr = new WeakReference<Disposable>(d);
  TestObserver<Object> to = new Maybe<Object>() {
    @Override
    protected void subscribeActual(MaybeObserver<? super Object> observer) {
      observer.onSubscribe(wr.get());
    };
  }
  .onTerminateDetach()
  .test();
  d = null;
  to.cancel();
  System.gc();
  Thread.sleep(200);
  to.assertEmpty();
  assertNull(wr.get());
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void cancelDetaches() throws Exception {
  Disposable d = Disposables.empty();
  final WeakReference<Disposable> wr = new WeakReference<Disposable>(d);
  TestObserver<Object> to = new Single<Object>() {
    @Override
    protected void subscribeActual(SingleObserver<? super Object> observer) {
      observer.onSubscribe(wr.get());
    };
  }
  .onTerminateDetach()
  .test();
  d = null;
  to.cancel();
  System.gc();
  Thread.sleep(200);
  to.assertEmpty();
  assertNull(wr.get());
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void cancelDetaches() throws Exception {
  Disposable d = Disposables.empty();
  final WeakReference<Disposable> wr = new WeakReference<Disposable>(d);
  TestObserver<Void> to = new Completable() {
    @Override
    protected void subscribeActual(CompletableObserver observer) {
      observer.onSubscribe(wr.get());
    };
  }
  .onTerminateDetach()
  .test();
  d = null;
  to.cancel();
  System.gc();
  Thread.sleep(200);
  to.assertEmpty();
  assertNull(wr.get());
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void errorDetaches() throws Exception {
  Disposable d = Disposables.empty();
  final WeakReference<Disposable> wr = new WeakReference<Disposable>(d);
  TestObserver<Integer> to = new Maybe<Integer>() {
    @Override
    protected void subscribeActual(MaybeObserver<? super Integer> observer) {
      observer.onSubscribe(wr.get());
      observer.onError(new TestException());
      observer.onError(new IOException());
    };
  }
  .onTerminateDetach()
  .test();
  d = null;
  System.gc();
  Thread.sleep(200);
  to.assertFailure(TestException.class);
  assertNull(wr.get());
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void just() throws Exception {
  o = new Object();
  WeakReference<Object> wr = new WeakReference<Object>(o);
  TestSubscriber<Object> ts = new TestSubscriber<Object>();
  Flowable.just(o).count().toFlowable().onTerminateDetach().subscribe(ts);
  ts.assertValue(1L);
  ts.assertComplete();
  ts.assertNoErrors();
  o = null;
  System.gc();
  Thread.sleep(200);
  Assert.assertNull("Object retained!", wr.get());
}

代码示例来源：origin: ReactiveX/RxJava

@Test
public void backpressured() throws Exception {
  o = new Object();
  WeakReference<Object> wr = new WeakReference<Object>(o);
  TestSubscriber<Object> ts = new TestSubscriber<Object>(0L);
  Flowable.just(o).count().toFlowable().onTerminateDetach().subscribe(ts);
  ts.assertNoValues();
  ts.request(1);
  ts.assertValue(1L);
  ts.assertComplete();
  ts.assertNoErrors();
  o = null;
  System.gc();
  Thread.sleep(200);
  Assert.assertNull("Object retained!", wr.get());
}