[XSTR-680] Concurrent use of XStream instance with shared output stream leads to exception

Details

Type: Bug
Status: Closed
Priority: Major
Resolution: Not A Bug
Affects Version/s: 1.4.1
Fix Version/s: None
Component/s: Core, IO
Labels:
None

JDK version and platform:
Java HotSpot Server VM "1.6.0_07"; Linux

Description

Hi,

I get an exception when using an XStream instance from different threads that pass the same output stream to the XStream instance. I'll attach a small example to illustrate the problem. Please see the stack trace below.

Is this a bug or am I misreading the documentation? It says that the XStream instance can be shared across multiple threads and doesn't specify any constraints on the parameters given to the serializing/deserializing methods.

Thanks!

Exception in thread "Thread-19" com.thoughtworks.xstream.io.StreamException: : Writing text without an opened node
at com.thoughtworks.xstream.io.StatefulWriter.setValue(StatefulWriter.java:120)
at com.thoughtworks.xstream.io.WriterWrapper.setValue(WriterWrapper.java:45)
at com.thoughtworks.xstream.converters.extended.EncodedByteArrayConverter.marshal(EncodedByteArrayConverter.java:43)
at com.thoughtworks.xstream.core.AbstractReferenceMarshaller.convert(AbstractReferenceMarshaller.java:69)
at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:59)
at com.thoughtworks.xstream.core.TreeMarshaller.convertAnother(TreeMarshaller.java:44)
at com.thoughtworks.xstream.core.TreeMarshaller.start(TreeMarshaller.java:79)
at com.thoughtworks.xstream.core.AbstractTreeMarshallingStrategy.marshal(AbstractTreeMarshallingStrategy.java:37)
at com.thoughtworks.xstream.XStream.marshal(XStream.java:877)
at com.thoughtworks.xstream.XStream.marshal(XStream.java:866)
at com.thoughtworks.xstream.XStream$1.writeToStream(XStream.java:1626)
at com.thoughtworks.xstream.core.util.CustomObjectOutputStream.write(CustomObjectOutputStream.java:138)
at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:202)
at sun.nio.cs.StreamEncoder.implFlushBuffer(StreamEncoder.java:272)
at sun.nio.cs.StreamEncoder.implFlush(StreamEncoder.java:276)
at sun.nio.cs.StreamEncoder.flush(StreamEncoder.java:122)
at java.io.OutputStreamWriter.flush(OutputStreamWriter.java:212)
at com.thoughtworks.xstream.core.util.QuickWriter.flush(QuickWriter.java:75)
at com.thoughtworks.xstream.io.xml.PrettyPrintWriter.endNode(PrettyPrintWriter.java:316)
at com.thoughtworks.xstream.io.WriterWrapper.endNode(WriterWrapper.java:37)
at com.thoughtworks.xstream.io.path.PathTrackingWriter.endNode(PathTrackingWriter.java:48)
at com.thoughtworks.xstream.core.TreeMarshaller.start(TreeMarshaller.java:80)
at com.thoughtworks.xstream.core.AbstractTreeMarshallingStrategy.marshal(AbstractTreeMarshallingStrategy.java:37)
at com.thoughtworks.xstream.XStream.marshal(XStream.java:877)
at com.thoughtworks.xstream.XStream.marshal(XStream.java:866)
at com.thoughtworks.xstream.XStream.toXML(XStream.java:854)
at XStreamTest4$2.run(XStreamTest4.java:27)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.IllegalStateException: Writing text without an opened node
... 28 more

Options
- Sort By Name
- Sort By Date
- Ascending
- Descending
- Download All

Attachments

XStreamTest4.java

12/Oct/11 7:03 AM

0.8 kB

Michael Pradel

Activity

Hide

Permalink

Jörg Schaible added a comment - 12/Oct/11 7:44 AM

You cannot expect something useful when you write concurrently into the same stream. This is true for XStream as well as for the JDK serialization:

private void run() throws Exception
{
  for (int i = 0; i < 25; i++) {
    final ObjectOutputStream os = new ObjectOutputStream(new ByteArrayOutputStream());

    Thread t1 =
        new Thread(new Runnable() {
          public void run()
          {
            try {
              os.writeObject(new ArrayList());
            } catch (IOException e) {
              throw new Error(e);
            }
          }
        });
    Thread t2 =
        new Thread(new Runnable() {
          public void run()
          {
            try {
              os.writeObject(new ArrayList());
            } catch (IOException e) {
              throw new Error(e);
            }
          }
        });
    t1.start();
    t2.start();
    try {
      t1.join();
      t2.join();
    } catch (InterruptedException ie) {
    }
  }
}

You can safely use the same XStream instance in parallel to write into different streams. What should it good for, to write two different object graphs in parallel into the same stream anyway?

Please, if you have questions, use the user's list.

Show

Jörg Schaible added a comment - 12/Oct/11 7:44 AM You cannot expect something useful when you write concurrently into the same stream. This is true for XStream as well as for the JDK serialization: private void run() throws Exception { for ( int i = 0; i < 25; i++) { final ObjectOutputStream os = new ObjectOutputStream( new ByteArrayOutputStream()); Thread t1 = new Thread ( new Runnable () { public void run() { try { os.writeObject( new ArrayList()); } catch (IOException e) { throw new Error(e); } } }); Thread t2 = new Thread ( new Runnable () { public void run() { try { os.writeObject( new ArrayList()); } catch (IOException e) { throw new Error(e); } } }); t1.start(); t2.start(); try { t1.join(); t2.join(); } catch (InterruptedException ie) { } } } You can safely use the same XStream instance in parallel to write into different streams. What should it good for, to write two different object graphs in parallel into the same stream anyway? Please, if you have questions, use the user's list.

Concurrent use of XStream instance with shared output stream leads to exception

Details

Description

Attachments

Activity

People

Dates