I was running my project in eclipse with apache tomcat server without any problems. I don't know what it is, but the project started giving errors during operation. I can't find a bug in the codes I've written. It shows my filter class as the cause of the error, but the filter class is the same as before the project gave an error, so I haven't made any changes to it. The error shown on the console:

java.lang.UnsupportedClassVersionError: Preview features are not enabled for com/Filter/AdminFilter (class file version 61.65535). Try running with '--enable-preview' (unable to load class [com.Filter.AdminFilter])
at org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2494)
at org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:875)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1376)
at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1220)
at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:534)
at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:515)
at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:149)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:251)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:102)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4613)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5256)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:726)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:698)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:696)
at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:690)
at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1889)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:123)
at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:583)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:473)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1618)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:319)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:123)
at org.apache.catalina.util.LifecycleBase.setStateInternal(LifecycleBase.java:423)
at org.apache.catalina.util.LifecycleBase.setState(LifecycleBase.java:366)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:946)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:835)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1396)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1386)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:145)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:919)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:263)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:432)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:927)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.startup.Catalina.start(Catalina.java:772)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:345)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:476)

AdminFilter Class:

import java.io.IOException;


import javax.servlet.DispatcherType;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
* Servlet Filter implementation class AdminFilter
*/
@WebFilter(dispatcherTypes = {
      DispatcherType.FORWARD,
      DispatcherType.REQUEST,
      DispatcherType.INCLUDE
} , urlPatterns = {"/secrutiy/*"})
public class AdminFilter extends HttpFilter implements Filter {
     
  /**
   * 
   */
  private static final long serialVersionUID = 4806046144481735173L;

  /**
   * @see HttpFilter#HttpFilter()
   */
  public AdminFilter() {
      super();
      // TODO Auto-generated constructor stub
  }

  /**
   * @see Filter#destroy()
   */
  public void destroy() {
      // TODO Auto-generated method stub
  }

  /**
   * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
   */
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
      if(((HttpServletRequest) request).getSession().getAttribute("userToken")!=null) {
          if(!((HttpServletRequest) request).getSession().getAttribute("role").equals("admin")) {
              
              ((HttpServletResponse) response).sendRedirect(request.getServletContext().getContextPath()  "/invalidUser.jsp");
          }
      }else {
          ((HttpServletResponse) response).sendRedirect(request.getServletContext().getContextPath()  "/login.jsp");
      }
      chain.doFilter(request, response);
  }

  /**
   * @see Filter#init(FilterConfig)
   */
  public void init(FilterConfig fConfig) throws ServletException {
      // TODO Auto-generated method stub
  }

}

Anyone now what is the problem? How can i solve that? Please help.

CodePudding user response：

But I couldn't figure out how I did it project Propeties --> Java Complier the "enable preview features for java 17" button on the screen has been activated. The problem was solved when I deactivated the button.