创建bat文件时如何解决java.lang.NoClassDefFoundError？

Question

I am trying to run bat file which should start my restCRUD server written in java. Project contains only one main method so my bath file looks like this:

java -jar TaxAppWebserver.jar

pause

The problem is that when I run bat file I get java.lang.NoClassDefFoundError.

Exception in thread "main" java.lang.NoClassDefFoundError: javax/persistence/Persistence
        at facade.FacadeLogic.<init>(FacadeLogic.java:17)
        at restCRUD.HandlerLogger.<init>(HandlerLogger.java:14)
        at restCRUD.RestFileServer.run(RestFileServer.java:22)
        at restCRUD.RestFileServer.main(RestFileServer.java:36)
Caused by: java.lang.ClassNotFoundException: javax.persistence.Persistence
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)

Line 17 from the FacadeLogic.java:

 EntityManagerFactory emf = Persistence.createEntityManagerFactory("TaxAppWebserverPU");

Can anyone give me a clue of what is wrong?

Answer 1

Rebuild your jar file with the missing jar added to the classpath in the MANIFEST.MF file. IDE's such as Eclipse can add these automatically when creating executable jar files

Class-Path: javax.persistence.jar

Answer 2

I solved the problem by creating lib folder in the project directory and copying all the external libraries to this folder. Also, I had to change my bat file for

java -cp TaxAppWebserver.jar restCRUD.RestFileServer

so that it knows where the main method is.