`PropertiesUtil` fails due to blank key lookup about logging-log4j2

[vy]

@jolly28, pushed a small fix in f0bd878. Could you see if the most recent 2.24.0-SNAPSHOT solves the problem, please? (Note that you need to add the snapshot repository to your pom.xml.)

[jolly28]

@vy I have used the latest log4j-api and log4j-core jars (2.24.0-SNAPSHOT). seems the issue is solved.

[vy]

@jolly28, could you try with the latest version of log4j-api (i.e., 2.23.1), please?

[ppkarwasz]

For context, this isssue is related to this SO question.

[vy]

@jolly28, in the SO question @ppkarwasz referenced, you(?) state that issue persists with 2.23.1 too. If so, could you share the stack trace you get while using 2.23.1, please?

[jolly28]

sure, @vy I am attaching the error stack trace I am getting while using the version 2.23.1.

SEVERE [main] org.apache.catalina.core.StandardContext.filterStart Exception starting filter [Struts2Filter]
        java.lang.ExceptionInInitializerError
                at org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter.<clinit>(StrutsPrepareAndExecuteFilter.java:49)
                at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
                at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:77)
                at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
                at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
                at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:480)
                at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:143)
                at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:242)
                at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:97)
                at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4311)
                at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:4940)
                at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:171)
                at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:683)
                at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:658)
                at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:661)
                at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:1014)
                at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1866)
                at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
                at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
                at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
                at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:123)
                at org.apache.catalina.startup.HostConfig.deployWARs(HostConfig.java:816)
                at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:468)
                at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1584)
                at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:312)
                at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:114)
                at org.apache.catalina.util.LifecycleBase.setStateInternal(LifecycleBase.java:402)
                at org.apache.catalina.util.LifecycleBase.setState(LifecycleBase.java:345)
                at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:893)
                at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:794)
                at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:171)
                at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1332)
                at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1322)
                at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
                at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
                at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:145)
                at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:866)
                at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:248)
                at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:171)
                at org.apache.catalina.core.StandardService.startInternal(StandardService.java:433)
                at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:171)
                at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:925)
                at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:171)
                at org.apache.catalina.startup.Catalina.start(Catalina.java:735)
                at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
                at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
                at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
                at java.base/java.lang.reflect.Method.invoke(Method.java:568)
                at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:345)
                at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:473)
        



Caused by: java.lang.IllegalArgumentException: key can't be empty
                at java.base/java.lang.System.checkKey(System.java:1049)
                at java.base/java.lang.System.getProperty(System.java:912)
                at org.apache.logging.log4j.util.SystemPropertiesPropertySource.getProperty(SystemPropertiesPropertySource.java:99)
                at org.apache.logging.log4j.util.SystemPropertiesPropertySource.containsProperty(SystemPropertiesPropertySource.java:107)
                at org.apache.logging.log4j.util.PropertiesUtil$Environment.lambda$reload$1(PropertiesUtil.java:514)
                at java.base/java.lang.Iterable.forEach(Iterable.java:75)
                at org.apache.logging.log4j.util.PropertiesUtil$Environment.lambda$reload$2(PropertiesUtil.java:513)
                at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
                at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:179)
                at java.base/java.util.HashMap$KeySpliterator.forEachRemaining(HashMap.java:1707)
                at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
                at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
                at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
                at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
                at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
                at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:596)
                at org.apache.logging.log4j.util.PropertiesUtil$Environment.reload(PropertiesUtil.java:510)
                at org.apache.logging.log4j.util.PropertiesUtil$Environment.<init>(PropertiesUtil.java:492)
                at org.apache.logging.log4j.util.PropertiesUtil$Environment.<init>(PropertiesUtil.java:465)
                at org.apache.logging.log4j.util.PropertiesUtil.<init>(PropertiesUtil.java:98)
                at org.apache.logging.log4j.util.PropertiesUtil.<init>(PropertiesUtil.java:90)
                at org.apache.logging.log4j.util.PropertiesUtil.lambda$static$0(PropertiesUtil.java:66)
                at org.apache.logging.log4j.util.LazyUtil$SafeLazy.value(LazyUtil.java:113)
                at org.apache.logging.log4j.util.Lazy.get(Lazy.java:39)
                at org.apache.logging.log4j.util.PropertiesUtil.getProperties(PropertiesUtil.java:132)
                at org.apache.logging.log4j.LogManager.<clinit>(LogManager.java:73)
                ... 50 more
```