可执行jar无法找到或加载主类

Question

I've been struggling with this common error and just can't resolve it. This application is composed of multiple packages and runs fine within JCreator (at the moment I need to use this IDE rather than Eclipse).

My manifest file is here (there are 2 blank lines at the end):

Manifest-Version: 1.0
Created-By: 1.6.0_45 (Sun Microsystems Inc.)
Main-Class: C:\COMPILE\MyProjects\douwe\classes\dykstra\dplus\main\DPMain

I wrote a bat file to create the jar:

jar -cvfm DPlus.jar C:\\COMPILE\\MyProjects\\douwe\\classes\\MANIFEST.MF C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\main*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\library*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\command*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\file*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\file\\display*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\command*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\file*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\file\\display*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\gui*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\gui*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\job*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\job*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\types*.class C:\\COMPILE\\MyProjects\\douwe\\classes\\dykstra\\dplus\\util*.class

When I try to execute with the command

C:\\COMPILE\\MyProjects\\douwe\\classes>java -jar DPlus.jar

I always get the error:

Error: Could not find or load main class C:\COMPILE\MyProjects\douwe\classes\dykstra\dplus\main\DPMain

Can anyone see what I'm doing wrong here?

Answer 1

Usually this error is due to MANIFEST.MF if the'res no application's entry point has been set. Your manifest file should have this line of code

Main-Class: YourPackage.DPMain

Alternatively, you can do the following.

java -cp .;app.jar YourPackage.DPMain

Answer 2

In my implementation, there are something different from yours, you can refer:

(1) The folder(before compressed) structure you need to add a META-INF folder and put your MANIFEST.MF in it

(2) The content in your MANIFEST.MF I think your should use the package format instead of a folder tree format:

Manifest-Version: 1.0
Main-Class: com.loadtest.mgr.LoadTestStarter