this error shown in console how to solve this issue first i want to know why it is coming continiously...........................
java.lang.UnsupportedClassVersionError: Bad version number in .class file (unable to load class ser)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2822)
at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1159)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1647)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1526)
at org.apache.catalina.startup.WebAnnotationSet.loadApplicationServletAnnotations(WebAnnotationSet.java:108)
at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:58)
at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:297)
at org.apache.catalina.startup.ContextConfig.start(ContextConfig.java:1078)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:261)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:142)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4611)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:799)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:779)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:601)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:675)
at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:601)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:502)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1383)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:306)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:142)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1385)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1649)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1658)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1638)
at java.lang.Thread.run(Unknown Source)
This error means that you compiled your Java sources with a newer version of Java than the one you are using to run your compiled JARs/classes.
If you cannot resolve the issue, provide us with more details about what you are doing, and what environment you are working in, and we might be able to provide more specific help.