The server encountered an unexpected condition that prevented it from fulfilling the request

I have two amazon instances, I have uploaded the same war in both instances, In one instance it is running properly(giving expected result) but in another instance it is giving the following error javax.servlet.ServletException: Servlet.init() for servlet [Example-RS] threw exception org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504) org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650) org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790) org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) java.lang.Thread.run(Thread.java:748) Root Cause java.lang.IncompatibleClassChangeError: Implementing class java.lang.ClassLoader.defineClass1(Native Method) java.lang.ClassLoader.defineClass(ClassLoader.java:763) java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2283) org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:811) org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1260) org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1119) com.sun.jersey.api.core.ScanningResourceConfig.init(ScanningResourceConfig.java:79) com.sun.jersey.api.core.PackagesResourceConfig.init(PackagesResourceConfig.java:104) com.sun.jersey.api.core.PackagesResourceConfig.(PackagesResourceConfig.java:78) com.sun.jersey.api.core.PackagesResourceConfig.(PackagesResourceConfig.java:89) com.sun.jersey.spi.container.servlet.WebComponent.createResourceConfig(WebComponent.java:700) com.sun.jersey.spi.container.servlet.WebComponent.createResourceConfig(WebComponent.java:678) com.sun.jersey.spi.container.servlet.WebComponent.init(WebComponent.java:203) com.sun.jersey.spi.container.servlet.ServletContainer.init(ServletContainer.java:374) com.sun.jersey.spi.container.servlet.ServletContainer.init(ServletContainer.java:557) javax.servlet.GenericServlet.init(GenericServlet.java:158) org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504) org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650) org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790) org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) java.lang.Thread.run(Thread.java:748) I google regarding this error, I got suggestion related to web.xml file, If it related to web.xml file then it should not be executed in another instance as well