使用common-logging与log4j打印日志，发现版本冲突

严重:   Error   reading   tld   listeners   java.lang.NullPointerException java.lang.NullPointerException at   org.apache.log4j.Category.isEnabledFor(Category.java:746) at   org.apache.commons.logging.impl.Log4JLogger.isTraceEnabled(Log4JLogger.java:327) at   org.apache.catalina.startup.TldConfig.tldScanResourcePaths(TldConfig.java:582) at   org.apache.catalina.startup.TldConfig.execute(TldConfig.java:283) at   org.apache.catalina.core.StandardContext.processTlds(StandardContext.java:4307) at   org.apache.catalina.core.StandardContext.start(StandardContext.java:4144) at   org.apache.catalina.core.StandardContext.reload(StandardContext.java:3025) at   org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:432) at   org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1278) at   org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1570) at   org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1579) at   org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1579) at   org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1559) at   java.lang.Thread.run(Thread.java:595)

解决办法：将common-logging的包换一个版本。我是换成了commons-logging-1.0.4.jar，