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javaxslt

XSLT in OpenJDK 17 gives NullPointerException (Bug in Xalan?)

I have used XSLT transformation many times in Java thus I am puzzled getting a NullPointerException.

This piece of code works without problem:

    Document doc = generateXml(catalog);
    
    Transformer transformer = TransformerFactory.newInstance().newTransformer();
    transformer.setOutputProperty(OutputKeys.INDENT, "yes");
    transformer.setOutputProperty(
         "{http://xml.apache.org/xslt}indent-amount", "4");
    transformer.transform(new DOMSource(doc), new StreamResult(out));

Now I want to use a different stylesheet, thus I change the code into that:

    Document doc = generateXml(catalog);
    
    URL stylesheet = getClass().getResource("catalog_html.xslt");
    log.debug("stylesheet url: {}", stylesheet);
    Transformer transformer = TransformerFactory.newInstance()
            .newTransformer(new StreamSource(stylesheet.openStream()));
    transformer.transform(new DOMSource(doc), new StreamResult(out));

From the debug log I know that styleheet is not null. Otherwise I would get a NullPointerException when creating the transformer. But instead I get a NullPointerException when executing the transformer, and it looks like this:

javax.xml.transform.TransformerException: javax.xml.transform.TransformerException: java.lang.NullPointerException: Cannot invoke "String.toCharArray()" because "data" is null
    at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:792) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:395) ~[?:?]
    at com.chaudhuri.cataloggenerator.Generator.writeHtml(Generator.java:318) ~[classes/:?]
    at com.chaudhuri.cataloggenerator.Generator.lambda$run$3(Generator.java:248) ~[classes/:?]
    at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:992) ~[?:?]
    at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:762) ~[?:?]
    at com.chaudhuri.cataloggenerator.Generator.run(Generator.java:230) ~[classes/:?]
    at com.chaudhuri.cataloggenerator.GeneratorTest.testRun4(GeneratorTest.java:193) ~[test-classes/:?]
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[?:?]
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
    at java.lang.reflect.Method.invoke(Method.java:568) ~[?:?]
    at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:727) ~[junit-platform-commons-1.9.2.jar:1.9.2]
    at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:156) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:147) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:86) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(InterceptingExecutableInvoker.java:103) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.lambda$invoke$0(InterceptingExecutableInvoker.java:93) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:92) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:86) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$7(TestMethodTestDescriptor.java:217) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:213) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:138) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:68) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:151) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at java.util.ArrayList.forEach(ArrayList.java:1511) ~[?:?]
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at java.util.ArrayList.forEach(ArrayList.java:1511) ~[?:?]
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:147) ~[junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:127) ~[junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:90) ~[junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:55) ~[junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:102) [junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:54) [junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114) [junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86) [junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86) [junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.apache.maven.surefire.junitplatform.LazyLauncher.execute(LazyLauncher.java:50) [surefire-junit-platform-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.junitplatform.JUnitPlatformProvider.execute(JUnitPlatformProvider.java:184) [surefire-junit-platform-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.junitplatform.JUnitPlatformProvider.invokeAllTests(JUnitPlatformProvider.java:148) [surefire-junit-platform-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.junitplatform.JUnitPlatformProvider.invoke(JUnitPlatformProvider.java:122) [surefire-junit-platform-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:385) [surefire-booter-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.booter.ForkedBooter.execute(ForkedBooter.java:162) [surefire-booter-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.booter.ForkedBooter.run(ForkedBooter.java:507) [surefire-booter-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:495) [surefire-booter-3.0.0.jar:3.0.0]
Caused by: javax.xml.transform.TransformerException: java.lang.NullPointerException: Cannot invoke "String.toCharArray()" because "data" is null
    at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getDOM(TransformerImpl.java:603) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:782) ~[?:?]
    ... 78 more
Caused by: java.lang.NullPointerException: Cannot invoke "String.toCharArray()" because "data" is null
    at com.sun.org.apache.xalan.internal.xsltc.trax.DOM2SAX.parse(DOM2SAX.java:294) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.DOM2SAX.parse(DOM2SAX.java:275) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.DOM2SAX.parse(DOM2SAX.java:275) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.DOM2SAX.parse(DOM2SAX.java:275) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.DOM2SAX.parse(DOM2SAX.java:192) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.DOM2SAX.parse(DOM2SAX.java:144) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.dom.XSLTCDTMManager.getDTM(XSLTCDTMManager.java:335) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.dom.XSLTCDTMManager.getDTM(XSLTCDTMManager.java:214) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getDOM(TransformerImpl.java:581) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:782) ~[?:?]
    ... 78 more

While I do not believe this is related to the stylesheet, well here it is:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
    <xsl:output method="html"/>

    <!-- TODO customize transformation rules 
         syntax recommendation http://www.w3.org/TR/xslt 
    -->
    <xsl:template match="/">
        <html>
            <head>
                <title>catalog_html.xsl</title>
            </head>
            <body>
            </body>
        </html>
    </xsl:template>

</xsl:stylesheet>

Any ideas what could be the cause?

Edit

Just to see whether the problem was in the StreamSource, I changed my code to

    Document doc = generateXml(catalog);
    
    URL stylesheet = getClass().getResource("catalog_html.xslt");
    Document ss = DocumentBuilderFactory.newInstance()
                                        .newDocumentBuilder()
                                        .parse(stylesheet.openStream());
    Transformer transformer = 
        TransformerFactory.newInstance()
                          .newTransformer(new DOMSource(ss));
    transformer.transform(new DOMSource(doc), new StreamResult(out));

So I am parsing the stylesheet myself before injecting it as DOM structure into the transformer. This time I get another exception when initializing the transformer:

javax.xml.transform.TransformerConfigurationException: Cannot invoke "String.hashCode()" because "this._stringRep" is null
    at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl.newTemplates(TransformerFactoryImpl.java:1077) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl.newTransformer(TransformerFactoryImpl.java:834) ~[?:?]
    at com.chaudhuri.cataloggenerator.Generator.writeHtml(Generator.java:319) ~[classes/:?]
    at com.chaudhuri.cataloggenerator.Generator.lambda$run$3(Generator.java:249) ~[classes/:?]
    at java.util.Spliterators$ArraySpliterator.forEachRemaining(Spliterators.java:992) ~[?:?]
    at java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:762) ~[?:?]
    at com.chaudhuri.cataloggenerator.Generator.run(Generator.java:231) ~[classes/:?]
    at com.chaudhuri.cataloggenerator.GeneratorTest.testRun4(GeneratorTest.java:193) ~[test-classes/:?]
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
    at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[?:?]
    at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
    at java.lang.reflect.Method.invoke(Method.java:568) ~[?:?]
    at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:727) ~[junit-platform-commons-1.9.2.jar:1.9.2]
    at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:131) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:156) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:147) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:86) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(InterceptingExecutableInvoker.java:103) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.lambda$invoke$0(InterceptingExecutableInvoker.java:93) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:106) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:64) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:45) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:37) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:92) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.execution.InterceptingExecutableInvoker.invoke(InterceptingExecutableInvoker.java:86) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$7(TestMethodTestDescriptor.java:217) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:213) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:138) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:68) ~[junit-jupiter-engine-5.9.2.jar:5.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:151) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at java.util.ArrayList.forEach(ArrayList.java:1511) ~[?:?]
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at java.util.ArrayList.forEach(ArrayList.java:1511) ~[?:?]
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:41) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$6(NodeTestTask.java:155) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:141) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:137) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$9(NodeTestTask.java:139) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:138) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:95) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:35) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:54) ~[junit-platform-engine-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:147) ~[junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:127) ~[junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:90) ~[junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.lambda$execute$0(EngineExecutionOrchestrator.java:55) ~[junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.withInterceptedStreams(EngineExecutionOrchestrator.java:102) [junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.EngineExecutionOrchestrator.execute(EngineExecutionOrchestrator.java:54) [junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:114) [junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:86) [junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.junit.platform.launcher.core.DefaultLauncherSession$DelegatingLauncher.execute(DefaultLauncherSession.java:86) [junit-platform-launcher-1.9.2.jar:1.9.2]
    at org.apache.maven.surefire.junitplatform.LazyLauncher.execute(LazyLauncher.java:50) [surefire-junit-platform-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.junitplatform.JUnitPlatformProvider.execute(JUnitPlatformProvider.java:184) [surefire-junit-platform-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.junitplatform.JUnitPlatformProvider.invokeAllTests(JUnitPlatformProvider.java:148) [surefire-junit-platform-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.junitplatform.JUnitPlatformProvider.invoke(JUnitPlatformProvider.java:122) [surefire-junit-platform-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:385) [surefire-booter-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.booter.ForkedBooter.execute(ForkedBooter.java:162) [surefire-booter-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.booter.ForkedBooter.run(ForkedBooter.java:507) [surefire-booter-3.0.0.jar:3.0.0]
    at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:495) [surefire-booter-3.0.0.jar:3.0.0]
Caused by: java.lang.NullPointerException: Cannot invoke "String.hashCode()" because "this._stringRep" is null
    at com.sun.org.apache.xalan.internal.xsltc.compiler.QName.<init>(QName.java:45) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.compiler.Parser.getQName(Parser.java:315) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.compiler.Parser.makeInstance(Parser.java:982) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.compiler.Parser.startElement(Parser.java:1312) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.DOM2SAX.parse(DOM2SAX.java:269) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.DOM2SAX.parse(DOM2SAX.java:192) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.DOM2SAX.parse(DOM2SAX.java:130) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.compiler.Parser.parse(Parser.java:439) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.compiler.XSLTC.compile(XSLTC.java:481) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.compiler.XSLTC.compile(XSLTC.java:575) ~[?:?]
    at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl.newTemplates(TransformerFactoryImpl.java:1036) ~[?:?]
    ... 78 more

It seems to be either my stylesheet or Xalan. But even if it were the stylesheet, I'd expect a better message from Xalan than that.

Solution

  • Martin Honnen had the key idea: Simply switch to Saxon HE. All I did was to add this dependency to my project:

    <!-- https://mvnrepository.com/artifact/net.sf.saxon/Saxon-HE -->
<dependency>
    <groupId>net.sf.saxon</groupId>
    <artifactId>Saxon-HE</artifactId>
    <version>12.3</version>
</dependency>

    Now the code runs without a single line changed. The issue must somehow be in the OpenJDK-embedded Xalan version, but it is no longer blocking me.