This happens consistently enough that it's presumably not a fluke:
java.util.concurrent.ExecutionException: java.lang.RuntimeException: Java compilation failed:
at java.base/java.util.concurrent.FutureTask.report(FutureTask.java:122)
at java.base/java.util.concurrent.FutureTask.get(FutureTask.java:191)
at org.openntf.nsfodp.compiler.servlet.ODPCompilerContainerServlet.doGet(ODPCompilerContainerServlet.java:213)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:693)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:806)
at org.eclipse.equinox.http.registry.internal.ServletManager$ServletWrapper.service(ServletManager.java:180)
at org.eclipse.equinox.http.servlet.internal.ServletRegistration.handleRequest(ServletRegistration.java:90)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.processAlias(ProxyServlet.java:111)
at org.eclipse.equinox.http.servlet.internal.ProxyServlet.service(ProxyServlet.java:59)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:806)
at com.ibm.domino.xsp.adapter.osgi.OSGIModule.invokeServlet(OSGIModule.java:167)
at com.ibm.domino.xsp.adapter.osgi.OSGIModule.access$0(OSGIModule.java:153)
at com.ibm.domino.xsp.adapter.osgi.OSGIModule$1.invokeServlet(OSGIModule.java:134)
at com.ibm.domino.xsp.adapter.osgi.AbstractOSGIModule.invokeServletWithNotesContext(AbstractOSGIModule.java:181)
at com.ibm.domino.xsp.adapter.osgi.OSGIModule.doService(OSGIModule.java:128)
at com.ibm.domino.xsp.adapter.osgi.OSGIService.doService(OSGIService.java:418)
at com.ibm.designer.runtime.domino.adapter.LCDEnvironment.doService(LCDEnvironment.java:371)
at com.ibm.designer.runtime.domino.adapter.LCDEnvironment.service(LCDEnvironment.java:327)
at com.ibm.domino.xsp.bridge.http.engine.XspCmdManager.service(XspCmdManager.java:302)
Caused by: java.lang.RuntimeException: Java compilation failed:
at org.openntf.nsfodp.compiler.ODPCompiler.compile(ODPCompiler.java:452)
at org.openntf.nsfodp.compiler.ODPCompiler.compile(ODPCompiler.java:337)
at org.openntf.nsfodp.compiler.servlet.ODPCompilerContainerServlet.lambda$3(ODPCompilerContainerServlet.java:210)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
at lotus.domino.NotesThread.run(Unknown Source)
Caused by: org.openntf.com.ibm.xsp.extlib.javacompiler.JavaCompilerException: Error while loading the compiled classes
at org.openntf.com.ibm.xsp.extlib.javacompiler.JavaSourceClassLoader.addClasses(JavaSourceClassLoader.java:253)
at org.openntf.com.ibm.xsp.extlib.javacompiler.JavaSourceClassLoader.addClasses(JavaSourceClassLoader.java:208)
at org.openntf.nsfodp.compiler.ODPCompiler.compileJavaSources(ODPCompiler.java:492)
at org.openntf.nsfodp.compiler.ODPCompiler.compile(ODPCompiler.java:391)
... 6 more
Caused by: java.util.ConcurrentModificationException
at java.base/java.util.HashMap.computeIfAbsent(HashMap.java:1221)
at org.openntf.com.ibm.xsp.extlib.javacompiler.JavaSourceClassLoader.findClass(JavaSourceClassLoader.java:151)
at java.base/java.lang.ClassLoader.loadClassHelper(ClassLoader.java:1197)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:1112)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:1095)
at org.openntf.com.ibm.xsp.extlib.javacompiler.JavaSourceClassLoader.addClasses(JavaSourceClassLoader.java:248)
... 9 more
This happens consistently enough that it's presumably not a fluke: