创建并执行 JAR 文件时出错

Question

I have a problem creating and executing a JAR file. I have already made a JAR file, but when I execute it with java -jar , I am getting an error Error: could not find and load main class... I make a JAR file with jar cvfm , but I execute it from C:\Program Files\Java\jdk1.70\

What's wrong with this?

Answer 1

To create an executable jar file you have to specify the entry point to the jar.Like this:

jar -cvfe "jar file name" "Main Class Name(Ex com.test.MainTest)" "Files to be included in the jar"

If you already have a jar file, you can update the manifest file by creating an "additions" file and running the command to include the main class:

Main-Class: Classname

and run command: jar ufm "jarfilename" "additions manifest"

Answer 2

Maybe an entry in your manifest is missing? You have to add your MainClass to the MANIFEST.MF - the entry needed is Main-Class: classname

For mor informations see here

Answer 3

Whenever we create the jar file, we pass the main-class parameter in Manifest.mf that is embed in the jar.

you have missed that part and now when you are executing its not able to identify the main class to execute from

http://www.skylit.com/javamethods/faqs/createjar.html might help