Tomcat subordinate project Times wrong: An internal error occurred during ADD Deployment.java.lang.NullPointerException

In tomcat upper deployment times error:

An internal error occurred during ADD Deployment.

Java.lang.NullPointerException

Check it out. This error generally occurs because the down project is inconsistent with the native JDK version.

Check it out. Found the imported class library error, deleted and re-select the JDK is good

Right-click the project name →properties→java Build path→libraries→ check JRE System library[sun jdk 1.5.0.22]→edit→ Select Workspace default JRE (Sun JDK 1.5.0.22) "→finish

Tomcat subordinate project Times wrong: An internal error occurred during ADD Deployment.java.lang.NullPointerException