java.lang.NoClassDefFoundError: org/w3c/tidy/Tidy not always, only sometimes

BirtRunn

Our program generates pdf reports using Birt 2.3.1 runtime in multi threaded mode.
We have standalone java programs which executes in multi-threaded mode where number of threads can be configured before starting the program.

I have observed sometimes when we increase the number of threads we get below exceptions and birt report engine keeps on throwing these exceptions continuously for few seconds (say 10-20 seconds) after which somehow it stops throwing exceptions and continues to generate pdf reports again. Also while throwing exceptions, it generates pdf reports but at a significant low speed.

Exception is as follows...

Jun 3, 2010 2:51:33 AM org.eclipse.birt.report.engine.api.impl.RunAndRenderTask doRun
SEVERE: Error happened while running the report.
java.lang.NoClassDefFoundError: org/w3c/tidy/Tidy
at org.eclipse.birt.report.engine.parser.HTMLTextParser.<init>(HTMLTextParser.java:55)
at org.eclipse.birt.report.engine.parser.TextParser.parse(TextParser.java:110)
at org.eclipse.birt.report.engine.layout.pdf.util.HTML2Content.processForeignData(HTML2Content.java:317)
at org.eclipse.birt.report.engine.layout.pdf.util.HTML2Content.html2Content(HTML2Content.java:297)
at org.eclipse.birt.report.engine.layout.pdf.emitter.PDFLayoutEmitter.startForeign(PDFLayoutEmitter.java:493)
at org.eclipse.birt.report.engine.layout.pdf.emitter.WrappedPDFLayoutEmitter.startForeign(WrappedPDFLayoutEmitter.java:333)
at org.eclipse.birt.report.engine.layout.pdf.emitter.PDFLayoutEmitterProxy.startForeign(PDFLayoutEmitterProxy.java:319)
at org.eclipse.birt.report.engine.emitter.CompositeContentEmitter.startForeign(CompositeContentEmitter.java:260)
at org.eclipse.birt.report.engine.emitter.ContentEmitterUtil.startContent(ContentEmitterUtil.java:75)
at org.eclipse.birt.report.engine.layout.html.HTMLTableLayoutEmitter.startContent(HTMLTableLayoutEmitter.java:144)
at org.eclipse.birt.report.engine.emitter.ContentEmitterAdapter.startForeign(ContentEmitterAdapter.java:165)
at org.eclipse.birt.report.engine.emitter.ContentEmitterUtil.startContent(ContentEmitterUtil.java:75)
at org.eclipse.birt.report.engine.layout.html.buffer.HTMLPageBuffer.startContent(HTMLPageBuffer.java:115)
at org.eclipse.birt.report.engine.layout.html.buffer.TableBreakBuffer.startContent(TableBreakBuffer.java:227)
at org.eclipse.birt.report.engine.layout.html.HTMLLeafItemLM.start(HTMLLeafItemLM.java:50)
at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:132)
at org.eclipse.birt.report.engine.layout.html.HTMLBlockStackingLM.layoutNodes(HTMLBlockStackingLM.java:68)
at org.eclipse.birt.report.engine.layout.html.HTMLStackingLM.layoutChildren(HTMLStackingLM.java:27)
at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:133)
at org.eclipse.birt.report.engine.layout.html.HTMLInlineStackingLM.resumeLayout(HTMLInlineStackingLM.java:104)
at org.eclipse.birt.report.engine.layout.html.HTMLInlineStackingLM.layoutNodes(HTMLInlineStackingLM.java:153)
at org.eclipse.birt.report.engine.layout.html.HTMLStackingLM.layoutChildren(HTMLStackingLM.java:27)
at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:133)
at org.eclipse.birt.report.engine.layout.html.HTMLBlockStackingLM.layoutNodes(HTMLBlockStackingLM.java:68)
at org.eclipse.birt.report.engine.layout.html.HTMLStackingLM.layoutChildren(HTMLStackingLM.java:27)
at org.eclipse.birt.report.engine.layout.html.HTMLTableBandLM.layoutChildren(HTMLTableBandLM.java:65)
at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:133)
at org.eclipse.birt.report.engine.layout.html.HTMLBlockStackingLM.layoutNodes(HTMLBlockStackingLM.java:68)
at org.eclipse.birt.report.engine.layout.html.HTMLStackingLM.layoutChildren(HTMLStackingLM.java:27)
at org.eclipse.birt.report.engine.layout.html.HTMLTableLM.layoutChildren(HTMLTableLM.java:76)
at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:133)
at org.eclipse.birt.report.engine.layout.html.HTMLBlockStackingLM.layoutNodes(HTMLBlockStackingLM.java:68)
at org.eclipse.birt.report.engine.layout.html.HTMLPageLM.layout(HTMLPageLM.java:90)
at org.eclipse.birt.report.engine.layout.html.HTMLReportLayoutEngine.layout(HTMLReportLayoutEngine.java:101)
at org.eclipse.birt.report.engine.api.impl.RunAndRenderTask.doRun(RunAndRenderTask.java:151)
at org.eclipse.birt.report.engine.api.impl.RunAndRenderTask.run(RunAndRenderTask.java:72)
at MyProgram.runAndRenderReport(MyProgram.java:961)
at MyProgram.run(MyProgram.java:192)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: org.w3c.tidy.Tidy
at org.eclipse.osgi.framework.internal.core.BundleLoader.findClassInternal(BundleLoader.java:481)
at org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:397)
at org.eclipse.osgi.framework.internal.core.BundleLoader.findClass(BundleLoader.java:385)
at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:87)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
... 39 more
Jun 3, 2010 2:51:33 AM org.eclipse.birt.report.engine.api.impl.RunAndRenderTask doRun
SEVERE: Error happened while running the report.
java.lang.NoClassDefFoundError: org/w3c/tidy/Tidy
at org.eclipse.birt.report.engine.parser.HTMLTextParser.<init>(HTMLTextParser.java:55)
at org.eclipse.birt.report.engine.parser.TextParser.parse(TextParser.java:110)
at org.eclipse.birt.report.engine.layout.pdf.util.HTML2Content.processForeignData(HTML2Content.java:317)
at org.eclipse.birt.report.engine.layout.pdf.util.HTML2Content.html2Content(HTML2Content.java:297)
at org.eclipse.birt.report.engine.layout.pdf.emitter.PDFLayoutEmitter.startForeign(PDFLayoutEmitter.java:493)
at org.eclipse.birt.report.engine.layout.pdf.emitter.WrappedPDFLayoutEmitter.startForeign(WrappedPDFLayoutEmitter.java:333)
at org.eclipse.birt.report.engine.layout.pdf.emitter.PDFLayoutEmitterProxy.startForeign(PDFLayoutEmitterProxy.java:319)
at org.eclipse.birt.report.engine.emitter.CompositeContentEmitter.startForeign(CompositeContentEmitter.java:260)
at org.eclipse.birt.report.engine.emitter.ContentEmitterUtil.startContent(ContentEmitterUtil.java:75)
at org.eclipse.birt.report.engine.layout.html.HTMLTableLayoutEmitter.startContent(HTMLTableLayoutEmitter.java:144)
at org.eclipse.birt.report.engine.emitter.ContentEmitterAdapter.startForeign(ContentEmitterAdapter.java:165)
at org.eclipse.birt.report.engine.emitter.ContentEmitterUtil.startContent(ContentEmitterUtil.java:75)
at org.eclipse.birt.report.engine.layout.html.buffer.HTMLPageBuffer.startContent(HTMLPageBuffer.java:115)
at org.eclipse.birt.report.engine.layout.html.buffer.TableBreakBuffer.startContent(TableBreakBuffer.java:227)
at org.eclipse.birt.report.engine.layout.html.HTMLLeafItemLM.start(HTMLLeafItemLM.java:50)
at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:132)
at org.eclipse.birt.report.engine.layout.html.HTMLBlockStackingLM.layoutNodes(HTMLBlockStackingLM.java:68)
at org.eclipse.birt.report.engine.layout.html.HTMLStackingLM.layoutChildren(HTMLStackingLM.java:27)
at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:133)
at org.eclipse.birt.report.engine.layout.html.HTMLInlineStackingLM.resumeLayout(HTMLInlineStackingLM.java:104)
at org.eclipse.birt.report.engine.layout.html.HTMLInlineStackingLM.layoutNodes(HTMLInlineStackingLM.java:153)
at org.eclipse.birt.report.engine.layout.html.HTMLStackingLM.layoutChildren(HTMLStackingLM.java:27)
at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:133)
at org.eclipse.birt.report.engine.layout.html.HTMLBlockStackingLM.layoutNodes(HTMLBlockStackingLM.java:68)
at org.eclipse.birt.report.engine.layout.html.HTMLStackingLM.layoutChildren(HTMLStackingLM.java:27)
at org.eclipse.birt.report.engine.layout.html.HTMLTableBandLM.layoutChildren(HTMLTableBandLM.java:65)
at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:133)
at org.eclipse.birt.report.engine.layout.html.HTMLBlockStackingLM.layoutNodes(HTMLBlockStackingLM.java:68)
at org.eclipse.birt.report.engine.layout.html.HTMLStackingLM.layoutChildren(HTMLStackingLM.java:27)
at org.eclipse.birt.report.engine.layout.html.HTMLTableLM.layoutChildren(HTMLTableLM.java:76)
at org.eclipse.birt.report.engine.layout.html.HTMLAbstractLM.layout(HTMLAbstractLM.java:133)
at org.eclipse.birt.report.engine.layout.html.HTMLBlockStackingLM.layoutNodes(HTMLBlockStackingLM.java:68)
at org.eclipse.birt.report.engine.layout.html.HTMLPageLM.layout(HTMLPageLM.java:90)
at org.eclipse.birt.report.engine.layout.html.HTMLReportLayoutEngine.layout(HTMLReportLayoutEngine.java:101)
at org.eclipse.birt.report.engine.api.impl.RunAndRenderTask.doRun(RunAndRenderTask.java:151)
at org.eclipse.birt.report.engine.api.impl.RunAndRenderTask.run(RunAndRenderTask.java:72)
at MyProgram.runAndRenderReport(MyProgram.java:961)
at MyProgram.run(MyProgram.java:192)
at java.lang.Thread.run(Unknown Source)

Strange thing is why sometimes it throws ?NoClassDefFoundError: org/w3c/tidy/Tidy? error and after few seconds automatically stops throwing the errors.

We need to get rid of these exceptions as those are slowing down our report generation process as well as unnecessarily blocks the resources.

If somebody knows, please let me know what are the reasons of such behavior and how to handle it?

Thanks in advance. Help is really appreciated.

JasonW

Any chance you can try this with BIRT 2.5.2?

Jason