源自：2-2 开发第一个自定义标签

怎么报空指针异常错误？

java.lang.NullPointerException

at org.apache.tomcat.util.descriptor.tld.TldResourcePath.hashCode(TldResourcePath.java:164)

at java.util.HashMap.hash(HashMap.java:338)

at java.util.HashMap.get(HashMap.java:556)

at org.apache.jasper.compiler.TldCache.getTaglibXml(TldCache.java:95)

at org.apache.jasper.compiler.TagLibraryInfoImpl.(TagLibraryInfoImpl.java:177)

at org.apache.jasper.compiler.Parser.parseTaglibDirective(Parser.java:421)

at org.apache.jasper.compiler.Parser.parseDirective(Parser.java:479)

at org.apache.jasper.compiler.Parser.parseElements(Parser.java:1435)

at org.apache.jasper.compiler.Parser.parse(Parser.java:139)

at org.apache.jasper.compiler.ParserController.doParse(ParserController.java:227)

at org.apache.jasper.compiler.ParserController.parse(ParserController.java:100)

at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:199)

at org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)

at org.apache.jasper.compiler.Compiler.compile(Compiler.java:336)

at org.apache.jasper.compiler.Compiler.compile(Compiler.java:323)

at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:585)

at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:363)

at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)

at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)

at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)

at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)

at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)

at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1099)

at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672)

at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520)

at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476)

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

at java.lang.Thread.run(Thread.java:745)

提问者：不为装逼

2016-08-25 15:38