I'm trying to diagnose and resolve what I believe is a serious memory leak with JAXBContext. However, despite many attempts to do so, I'm unsuccessful.
In short, my application uses a small and consistent amount of memory during the first 50 min of execution. After around 50 min, the number of classes/memory increases from less than 4,000 (classes) to around 8,000 (similar increase occurs with memory). It remains this way until about 1 hr and 16 min when the number of classes (as observed in YourKit) grows to about 246,000 during the next 15-20 min of execution.
Just about the same time memory/class usage increases my program starts uploading images to eBay server using EBay's Java SDK [com.ebay.sdk.pictureservice.eps].
I analyzed the Object Allocation Call Tree in YourKit and it seems my program calls the following methods:
public int uploadPictures(PhotoDisplayCodeType arg0, PictureInfo[] arg1) {
int arg2 = 0;
for (int arg3 = 0; arg3 < arg1.length; ++arg3) {
if (this.uploadPicture(arg0, arg1[arg3])) {
++arg2;
}
}
return arg2;
}
public boolean uploadPicture(PhotoDisplayCodeType arg0, PictureInfo arg1) {
UploadSiteHostedPicturesRequestType arg2 = new UploadSiteHostedPicturesRequestType();
if (arg0.equals(PhotoDisplayCodeType.SUPER_SIZE) || arg0.equals(PhotoDisplayCodeType.PICTURE_PACK)) {
arg2.setPictureSet(PictureSetCodeType.SUPERSIZE);
}
return this.UpLoadSiteHostedPicture(arg1, arg2);
}
public boolean UpLoadSiteHostedPicture(PictureInfo arg0, UploadSiteHostedPicturesRequestType arg1) {
ApiLogging arg2 = this.apiContext.getApiLogging();
System.out.println("Starting picture upload..");
try {
Document arg3 = this.marshal(arg1);
this.addAuthToken(arg3);
String arg4;
if (arg2 != null && arg2.isLogSOAPMessages()) {
arg4 = XmlUtil.getXmlStringFromDom(arg3);
this.logMessage("UploadSiteHostedPicturesRequest", arg4);
}
arg4 = this.xmlToString(arg3);
String arg5 = this.sendFile(arg0.getPictureFilePath(), arg4);
if (arg2 != null && arg2.isLogSOAPMessages()) {
Document arg6 = XmlUtil.createDom(arg5);
String arg7 = XmlUtil.getXmlStringFromDom(arg6);
this.logMessage("UploadSiteHostedPicturesResponse", arg7);
}
UploadSiteHostedPicturesResponseType arg9 = this.unmarshal(arg5);
arg0.setReponse(arg9);
if (arg9.getErrors() != null && arg9.getErrors().length != 0) {
if (arg9.getErrors().length > 0 && arg9.getAck() == AckCodeType.WARNING) {
arg0.setURL(arg9.getSiteHostedPictureDetails().getFullURL());
arg0.setErrorType("PICTURE SERVICE RESPONSE WARNING");
arg0.setErrorMessage(arg9.getErrors()[0].getShortMessage());
if (arg2 != null && arg2.isLogExceptions()) {
log.warn("PICTURE SERVICE RESPONSE WARNING");
log.warn(arg9.getErrors()[0].getShortMessage());
}
return true;
} else {
arg0.setErrorType("PICTURE SERVICE RESPONSE ERROR");
arg0.setErrorMessage(arg9.getErrors()[0].getShortMessage());
if (arg2 != null && arg2.isLogExceptions()) {
log.error("PICTURE SERVICE RESPONSE ERROR");
log.error(arg9.getErrors()[0].getShortMessage());
}
return false;
}
} else {
arg0.setURL(arg9.getSiteHostedPictureDetails().getFullURL());
return true;
}
} catch (Exception arg8) {
arg0.setErrorType("PICTURE SERVICE UPLOAD ERROR");
arg0.setErrorMessage(arg8.getMessage());
if (arg2 != null && arg2.isLogExceptions()) {
log.error("fail to upload picture to eBay picture server!");
log.error(arg8.getMessage());
}
return false;
}
}
private Document marshal(UploadSiteHostedPicturesRequestType arg0)
throws JAXBException, ParserConfigurationException {
**// Is this line causing memory leak?**
JAXBContext arg1 = JAXBContext.newInstance(new Class[] { UploadSiteHostedPicturesRequestType.class });
Marshaller arg2 = arg1.createMarshaller();
if (arg0 == null) {
arg0 = new UploadSiteHostedPicturesRequestType();
}
JAXBElement arg3 = (new ObjectFactory()).createUploadSiteHostedPicturesRequest(arg0);
DocumentBuilderFactory arg4 = DocumentBuilderFactory.newInstance();
arg4.setNamespaceAware(true);
DocumentBuilder arg5 = arg4.newDocumentBuilder();
Document arg6 = arg5.newDocument();
arg2.marshal(arg3, arg6);
return arg6;
}
My program calls uploadPictures() a few hundred times in a row. It seems to me that memory starts increasing dramatically right at about the time program calls this function.
Is my diagnoses correct? How can I fix it?
Update:
I found this related thread on SO. If my diagnoses is correct it seems to be a bug with version the of JAXBContext used by EBay SDK.
Update:
I tried resolving this problem by changing JAXBContext class to a singleton but unfortunately it did not solve the issue:
public class JAXBContextFactory {
private static JAXBContextFactory instance = new JAXBContextFactory();
private static final Map< String, JAXBContext > INSTANCES = new ConcurrentHashMap<String, JAXBContext>();
private JAXBContextFactory() {
}
/**
* Returns an existing JAXBContext if one for the particular namespace exists,
* else it creates an instance adds it to a internal map.
* @param contextPath the context path
* @throws JAXBException exception in creating context
* @return a created JAXBContext
*/
public JAXBContext getJaxBContext(final String contextPath) throws JAXBException {
JAXBContext context = INSTANCES.get(contextPath);
if (context == null) {
context = JAXBContext.newInstance(contextPath);
INSTANCES.put(contextPath, context);
}
return context;
}
/**
* Returns an existing JAXBContext if one for the particular namespace exists,
* else it creates an instance adds it to a internal map.
* @param contextPath the context path
* @throws JAXBException exception in creating context
* @return a created JAXBContext
*/
public JAXBContext getJaxBContext(final Class contextPath) throws JAXBException {
JAXBContext context = INSTANCES.get(contextPath.getName());
if (context == null) {
context = JAXBContext.newInstance(contextPath);
INSTANCES.put(contextPath.getName(), context);
}
return context;
}
/**
* Get instance.
* @return Instance of this factory
*/
public static JAXBContextFactory getInstance() {
return instance;
}
}
When I look at Inspections in YourKit under "Other memory oddities" the only problem I detect is 243,959 "Classes with same name". When I inspect classes I see they all contain the term 'JAXB' in them. Based on these observations I have a few questions:
1) Why isn't Singleton pattern solving problem of creating many JAXBContext?
2) Even without Singleton, why aren't all relevant classes being garbage collected once my application clearly finishes using them / uploading images? I don't reference the JAXBContext class after upload is complete.
Thanks!
In your marshal(UploadSiteHostedPicturesRequestType arg0) method you have the line
// Is this line causing memory leak?
JAXBContext arg1 = JAXBContext.newInstance(new Class[] { UploadSiteHostedPicturesRequestType.class });
Although this line is not strictly a memory-leak,
it uses much memory, and takes much CPU time,
because it creates a new heavy JAXBContext object every time.
After return from this method
the local variable JAXBContext arg1 is not referenced anymore,
but it will stay in memory until it is garbage-collected
(and this might not happen for a long time).
You should replace this line by
JAXBContext arg1 = JAXBContextFactory.getInstance().getJaxBContext(UploadSiteHostedPicturesRequestType.class);
This should give you big improvement in memory usage and CPU time.