Error in Portlet Web Project

2021-05-24T12:37:04Z

I am currenty following this tutorial to create a web project. I have 2 problems:

1. I got error after I added the web project and started the server as shown below:

demo-web is just another name for guestbook-web.
I followed the instructions in the tutorial strictly and did not skip the steps.
Errors printed in the console:

org.osgi.framework.BundleException: Could not resolve module: com.liferay.docs.demo.portlet [2195]_  Unresolved requirement: Import-Package: javax.servlet; version="[3.1.0,4.0.0)"_ [Sanitized]
	at org.eclipse.osgi.container.Module.start(Module.java:444)
	at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.incStartLevel(ModuleContainer.java:1682)
	at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.incStartLevel(ModuleContainer.java:1662)
	at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.doContainerStartLevel(ModuleContainer.java:1624)
	at org.eclipse.osgi.container.SystemModule.startWorker(SystemModule.java:264)
	at org.eclipse.osgi.container.Module.doStart(Module.java:581)
	at org.eclipse.osgi.container.Module.start(Module.java:449)
	at org.eclipse.osgi.container.SystemModule.start(SystemModule.java:188)
	at org.eclipse.osgi.internal.framework.EquinoxBundle.start(EquinoxBundle.java:428)
	at org.eclipse.osgi.internal.framework.EquinoxBundle.start(EquinoxBundle.java:447)
	at org.eclipse.osgi.launch.Equinox.start(Equinox.java:115)
	at com.liferay.portal.bootstrap.ModuleFrameworkImpl.startFramework(ModuleFrameworkImpl.java:389)
	at com.liferay.portal.module.framework.ModuleFrameworkUtilAdapter.startFramework(ModuleFrameworkUtilAdapter.java:100)
	at com.liferay.portal.spring.context.PortalContextLoaderListener.contextInitialized(PortalContextLoaderListener.java:309)
	at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4682)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5150)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:713)
	at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:690)
	at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:695)
	at org.apache.catalina.startup.HostConfig.deployDescriptor(HostConfig.java:631)
	at org.apache.catalina.startup.HostConfig$DeployDescriptor.run(HostConfig.java:1832)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
	at java.base/java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:118)
	at org.apache.catalina.startup.HostConfig.deployDescriptors(HostConfig.java:526)
	at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:425)
	at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1577)
	at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:309)
	at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:123)
	at org.apache.catalina.util.LifecycleBase.setStateInternal(LifecycleBase.java:424)
	at org.apache.catalina.util.LifecycleBase.setState(LifecycleBase.java:367)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:929)
	at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:831)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1377)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1367)
	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:140)
	at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:902)
	at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.StandardService.startInternal(StandardService.java:423)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:928)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
	at org.apache.catalina.startup.Catalina.start(Catalina.java:634)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:350)
	at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:492)

2. According to step 10 in the Deploying the Application section.
Select Widgets. In the Applications list, your application appears in the Sample category. Its name is Guestbook.

However, I only have Hellow World application in the category. I assume this is due to the demo-web error and hence the application does not exist yet.