我在 Netbeans IDE 中使用 tomcat 作为服务器制作了一个 notelog Web 项目。直到几天前它工作正常，即使我没有更改任何内容，它也开始显示错误。每当我运行我的notelog，然后尝试通过此处登录页面登录时，它都会在登录时向我显示此错误错误`HTTP Status 500 – Internal Server Error Type Exception Report
实例化 servlet 类 [com.ronak.signin] 的消息错误
说明 服务器遇到了阻止它完成请求的意外情况。
例外
javax.servlet.ServletException：错误实例化 servlet 类 [com.ronak.signin] org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java :92) org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687) org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) org.apache.coyote.http11.Http11Processor.service (Http11Processor.java:374) org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) org.apache.tomcat.util.net .NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707) org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) java.base/java.util.concurrent。ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread. java:61) java.base/java.lang.Thread.run(Thread.java:832) 根本原因
java.lang.RuntimeException: com.ronak.signin.(signin.java:1) java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance( NativeConstructorAccessorImpl.java:64) java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500) java.base/ java.lang.reflect.Constructor.newInstance(Constructor.java:481) org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java: 92) org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687) org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357) org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) org.apache.coyote.AbstractProtocol$ConnectionHandler.process( AbstractProtocol.java:893) org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707) org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) java。 base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) org.apache.tomcat.util.threads。 TaskThread$WrappingRunnable.run(TaskThread.java:61) java.base/java.lang.Thread.run(Thread.java:832) 注意服务器日志中提供了根本原因的完整堆栈跟踪。服务（Http11Processor.java:374）org.apache.coyote.AbstractProcessorLight.process（AbstractProcessorLight.java:65）org.apache.coyote.AbstractProtocol$ConnectionHandler.process（AbstractProtocol.java:893）org.apache.tomcat.util。 net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707) org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor. java:1130) java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) java。 base/java.lang.Thread.run(Thread.java:832) 注意服务器日志中提供了根本原因的完整堆栈跟踪。服务（Http11Processor.java:374）org.apache.coyote.AbstractProcessorLight.process（AbstractProcessorLight.java:65）org.apache.coyote.AbstractProtocol$ConnectionHandler.process（AbstractProtocol.java:893）org.apache.tomcat.util。 net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707) org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor. java:1130) java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630) org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) java。 base/java.lang.Thread.run(Thread.java:832) 注意服务器日志中提供了根本原因的完整堆栈跟踪。java:65) org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707) org.apache.tomcat。 util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run( ThreadPoolExecutor.java:630) org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) java.base/java.lang.Thread.run(Thread.java:832) 注意完整的堆栈服务器日志中提供了根本原因的跟踪。java:65) org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:893) org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1707) org.apache.tomcat。 util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run( ThreadPoolExecutor.java:630) org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) java.base/java.lang.Thread.run(Thread.java:832) 注意完整的堆栈服务器日志中提供了根本原因的跟踪。SocketProcessorBase.run(SocketProcessorBase.java:49) java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java: 630) org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) java.base/java.lang.Thread.run(Thread.java:832) 注意根的完整堆栈跟踪原因在服务器日志中可用。SocketProcessorBase.run(SocketProcessorBase.java:49) java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130) java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java: 630) org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) java.base/java.lang.Thread.run(Thread.java:832) 注意根的完整堆栈跟踪原因在服务器日志中可用。832) 注意根本原因的完整堆栈跟踪可在服务器日志中找到。832) 注意根本原因的完整堆栈跟踪可在服务器日志中找到。. I have also tried to clean and build but it shows this error [error: option -Xbootclasspath/p: not allowed with target 15][3] ant -f C:\Java\Notelog -Dnb.internal.action.name=rebuild -DforceRedeploy=false -Dbrowser.context=C:\Java\Notelog clean dist init: undeploy-clean: Undeploying ... undeploy?path= /Notelog OK - 上下文路径中未部署的应用程序 [/Notelog] deps-clean: do-clean: 删除目录 C:\Java\Notelog\build check-clean: clean: init: deps-module-jar: deps-ear-jar : deps-jar: 创建目录：C:\Java\Notelog\build\web\WEB-INF\classes 创建目录：C:\Java\Notelog\build\web\META-INF 复制 1 个文件到 C:\Java\ Notelog\build\web\META-INF 将 15 个文件复制到 C:\Java\Notelog\build\web library-inclusion-in-archive: library-inclusion-in-manifest: Created dir: C:\Java\Notelog\build \empty Created dir: C:\Java\Notelog\build\generated-sources\ap-source-output 编译 8 个源文件到 C:\Java\Notelog\build\web\WEB-INF\classes 错误：选项 -Xbootclasspath/磷：目标 15 BUILD FAILED 不允许（总时间：0 秒）` 这是我的 signin.jsp 代码signin.jsp这是我的登录 servlet在此处输入图像描述。我尝试了许多解决方案，但仍然无法使其正常工作。欢迎任何帮助。
