Brian Burkhalter b890c3ce83 8147615: (fc) FileChannelImpl has no finalizer
Add a cleaner to close parent-less FileChannels

Reviewed-by: alanb, rriggs
2017-10-10 09:55:14 -07:00

88 lines
3.3 KiB
Java

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/* @test
* @bug 8147615
* @summary Test whether an unreferenced FileChannel is actually cleaned
* @requires (os.family == "linux") | (os.family == "mac") | (os.family == "solaris") | (os.family == "aix")
* @modules java.management
* @run main/othervm CleanerTest
*/
import com.sun.management.UnixOperatingSystemMXBean;
import java.lang.management.ManagementFactory;
import java.lang.management.OperatingSystemMXBean;
import java.lang.ref.PhantomReference;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.nio.channels.FileChannel;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
public class CleanerTest {
public static void main(String[] args) throws Throwable {
OperatingSystemMXBean mxBean =
ManagementFactory.getOperatingSystemMXBean();
UnixOperatingSystemMXBean unixMxBean = null;
if (mxBean instanceof UnixOperatingSystemMXBean) {
unixMxBean = (UnixOperatingSystemMXBean)mxBean;
} else {
System.out.println("Non-Unix system: skipping test.");
return;
}
Path path = Paths.get(System.getProperty("test.dir", "."), "junk");
try {
FileChannel fc = FileChannel.open(path, StandardOpenOption.CREATE,
StandardOpenOption.READ, StandardOpenOption.WRITE);
ReferenceQueue refQueue = new ReferenceQueue();
Reference fcRef = new PhantomReference(fc, refQueue);
long fdCount0 = unixMxBean.getOpenFileDescriptorCount();
fc = null;
// Perform repeated GCs until the reference has been enqueued.
do {
Thread.sleep(1);
System.gc();
} while (refQueue.poll() == null);
// Loop until the open file descriptor count has been decremented.
while (unixMxBean.getOpenFileDescriptorCount() > fdCount0 - 1) {
Thread.sleep(1);
}
long fdCount = unixMxBean.getOpenFileDescriptorCount();
if (fdCount != fdCount0 - 1) {
throw new RuntimeException("FD count expected " +
(fdCount0 - 1) + "; actual " + fdCount);
}
} finally {
Files.delete(path);
}
}
}