Summary of some common error exception handling methods in Java

Problem description

Problem Situation

Problem solving

Serious: StandardServer.await: create[8005]:

java.net.BindException: Address already in use: JVM_Bind

• Tomcat.exe running standalone is not closed

• Install other software and occupy port 8080

• Close the tomcat icon and end the tomcat process

• The default port for tomcat installation is 8080. Scheme 1: Change the port conf/service.xml of tomcat. Scheme 2: Open the cmd command prompt, enter netstat -ano and find the pid number occupied by port 8080, and then turn on the task manager details to close the pid number process.

Error configuring application listener of class org.springframework.web.context.ContextLoaderListener

java.lang.ClassNotFoundException: org.springframework.web.context.ContextLoaderListener

Spring 3.0 Web Libraries package not introduced

Rebuild the project and introduce the Spring 3.0 Web Libraries package when adding the Spring package

java.lang.ClassCastException: java.lang.Integer cannot be cast to java.util.List

Object o=session.getAttribute(a);

List l = (List)o;

Cannot convert object to List

It cannot be solved, I have found a lot of them, and they all say that they can be converted, but I can't use it.

I will convert the object object into a String object and then put it in the list

String s=session.getA...(a).toString();

List<String> l=new ArrayList();

L.add(s);

Errors occurred during the build.

Errors running builder 'DeploymentBuilder' on project 'Project name'.

java.lang.NullPointerException

This problem usually occurs when Myeclipse saves files and deploys them automatically. When writing the project, before I could deploy it, I closed myeclipse 10, and this happened. There is a reason for this error because this project is not created by myeclipse, needs to check the .project file and add com.genuitec.eclipse.j2eedt.core.webnature.

1. First close the MyEclipse workspace.

2. Then delete "/.metadata/.plugins/org.eclipse.core.runtime/.settings/com.genuitec.eclipse.ast.deploy.core.prefs" in the workspace

Cancel the automatic deployment of myeclipse:

Right-click on the project ->properties ->Builders, and check DeploymentBuilder to remove.

Js file error

Select js right-click->MyEclipse->Exclude From Validation Check

The J2EE project in Eclipse is run in MyEclipse, and the servlet file is reported as an error

Select a place where the servlet error is reported and add a javaee.jar package to enter

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'by publishDate desc limit 0,8' at line 1

There is a problem with the injected database statement

Pay special attention to the problem of spaces in statements on both sides of "+x+"

Clicking the deployment button is invalid

Find the working path of MyEclipse, go to "/.metadata/.plugins/org.eclipse.core.runtime/.settings" to find a .prefs file containing deploy to delete (com.genuitec.eclipse.ast.deploy.core.prefs). Restart MyEclipse and it's OK again.

Type Action question!list cannot be found in the namespace /

Window-->Preference-->Myeclipse->Validation->Removing the Build column checkmark after struts2 Validator confirms

(If it doesn't work, you can remove all build columns, it's useless)