[PATCH] XSLTC resource leak causes 'No more DTM IDs are available' error

The Xalan XSLT compiler (XSLTC) has several resource leaks in handling
result tree fragments in XSLT variables and parameters. If a variable
or parameter declaration contains XML elements, a new DOM tree is created
and a new internal integer id is reserved for it. The garbage collector can
never retrieve this DOM tree, because the id registration holds a reference
to it. This bug prevents the transformation of large input files, because
complex templates creates many result tree fragments and exceeds often the
absolute limit of possible DOM trees in XSLTC (2^16 = 65535). If this
limit is reached, XSLTC throws the following exception:

DTMException: No more DTM IDs are available

The attached patch adds a new release method to the DOM interface and calls
it, when the scope of a variable or parameter is leaved.

You can test this patch with the attached JAR file. This file can be
called with

java -Xmx800M -jar DOMLeak-XSLT-Test-X.Y.jar

This file contains four test style sheets with expected output files.

This bug exists also in all Sun JRE 1.5 and 1.6 versions, because the
Xalan XSLTC source code is used in the 'com.sun.org.apache.xalan.internal'
packages. The attached test JAR file contains also a patch for the current
Sun JRE version 1.6.0_5 and a fix JAR file to be installed into the
'../jre/lib/endorsed' directory of the JRE installation.

Please add the attached test files to the Xalan test suite. I have
released them under Apache license version 2.0.

Helge Schulz - http://OpenSHORE.org

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Here is the output of running my test cases with several Java version:

test:
apply-with-all-versions:
[apply] Buildfile: build.xml
[apply] test-java:
[apply] [echo] Test Sun Java 1.4.2_17 with integrated XSLT
[apply] [java] Testing DOMLeak-1-ResultTreeInVariable.xsl... Ok.
[apply] [java] Testing DOMLeak-2-ResultTreeInCallParameter.xsl... Ok.
[apply] [java] Testing DOMLeak-3-ResultTreeInApplyParameter.xsl... Ok.
[apply] [java] Testing DOMLeak-4-NodeSetAndMultiDOM.xsl... Ok.
[apply] [echo]
[apply] [echo] Test Sun Java 1.4.2_17 with latest Xalan (SVN revision 584164)
[apply] [java] Testing DOMLeak-1-ResultTreeInVariable.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: org.apache.xml.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-2-ResultTreeInCallParameter.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: org.apache.xml.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-3-ResultTreeInApplyParameter.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: org.apache.xml.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-4-NodeSetAndMultiDOM.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: org.apache.xml.dtm.DTMException: No more DTM IDs are available
[apply] [echo]
[apply] [echo] Test Sun Java 1.4.2_17 with fixed Xalan
[apply] [java] Testing DOMLeak-1-ResultTreeInVariable.xsl... Ok.
[apply] [java] Testing DOMLeak-2-ResultTreeInCallParameter.xsl... Ok.
[apply] [java] Testing DOMLeak-3-ResultTreeInApplyParameter.xsl... Ok.
[apply] [java] Testing DOMLeak-4-NodeSetAndMultiDOM.xsl... Ok.
[apply] BUILD SUCCESSFUL
[apply] Total time: 1 minute 21 seconds
[apply] Buildfile: build.xml
[apply] test-java:
[apply] [echo] Test Sun Java 1.5.0_15 with integrated XSLT
[apply] [java] Testing DOMLeak-1-ResultTreeInVariable.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: com.sun.org.apache.xml.internal.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-2-ResultTreeInCallParameter.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: com.sun.org.apache.xml.internal.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-3-ResultTreeInApplyParameter.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: com.sun.org.apache.xml.internal.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-4-NodeSetAndMultiDOM.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: com.sun.org.apache.xml.internal.dtm.DTMException: No more DTM IDs are available
[apply] [echo]
[apply] [echo] Test Sun Java 1.5.0_15 with latest Xalan (SVN revision 584164)
[apply] [java] Testing DOMLeak-1-ResultTreeInVariable.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: org.apache.xml.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-2-ResultTreeInCallParameter.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: org.apache.xml.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-3-ResultTreeInApplyParameter.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: org.apache.xml.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-4-NodeSetAndMultiDOM.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: org.apache.xml.dtm.DTMException: No more DTM IDs are available
[apply] [echo]
[apply] [echo] Test Sun Java 1.5.0_15 with fixed Xalan
[apply] [java] Testing DOMLeak-1-ResultTreeInVariable.xsl... Ok.
[apply] [java] Testing DOMLeak-2-ResultTreeInCallParameter.xsl... Ok.
[apply] [java] Testing DOMLeak-3-ResultTreeInApplyParameter.xsl... Ok.
[apply] [java] Testing DOMLeak-4-NodeSetAndMultiDOM.xsl... Ok.
[apply] BUILD SUCCESSFUL
[apply] Total time: 2 minutes 13 seconds
[apply] Buildfile: build.xml
[apply] test-java:
[apply] [echo] Test Sun Java 1.6.0_05 with integrated XSLT
[apply] [java] Testing DOMLeak-1-ResultTreeInVariable.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: com.sun.org.apache.xml.internal.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-2-ResultTreeInCallParameter.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: com.sun.org.apache.xml.internal.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-3-ResultTreeInApplyParameter.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: com.sun.org.apache.xml.internal.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-4-NodeSetAndMultiDOM.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: com.sun.org.apache.xml.internal.dtm.DTMException: No more DTM IDs are available
[apply] [echo]
[apply] [echo] Test Sun Java 1.6.0_05 with latest Xalan (SVN revision 584164)
[apply] [java] Testing DOMLeak-1-ResultTreeInVariable.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: org.apache.xml.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-2-ResultTreeInCallParameter.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: org.apache.xml.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-3-ResultTreeInApplyParameter.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: org.apache.xml.dtm.DTMException: No more DTM IDs are available
[apply] [java] Testing DOMLeak-4-NodeSetAndMultiDOM.xsl... ERROR: 'No more DTM IDs are available'
[apply] [java] XSLT Exception: org.apache.xml.dtm.DTMException: No more DTM IDs are available
[apply] [echo]
[apply] [echo] Test Sun Java 1.6.0_05 with fixed Xalan
[apply] [java] Testing DOMLeak-1-ResultTreeInVariable.xsl... Ok.
[apply] [java] Testing DOMLeak-2-ResultTreeInCallParameter.xsl... Ok.
[apply] [java] Testing DOMLeak-3-ResultTreeInApplyParameter.xsl... Ok.
[apply] [java] Testing DOMLeak-4-NodeSetAndMultiDOM.xsl... Ok.
[apply] BUILD SUCCESSFUL
[apply] Total time: 1 minute 42 seconds
BUILD SUCCESSFUL
Total time: 5 minutes 22 seconds