Program runs in Eclipse, but exported runnable jar file will not open?

Question

It looks like this is a common problem, but none of the previous posts seem to address my issue.

I believe I've narrowed it down to one problem. Any application that uses an InputStream will not open, but all my other applications run fine.

The application runs fine in Eclipse, but the window won't even open when I try to run the jar file.

Task manager shows it pop up for about a second or two, and then disappears.

I have tried all three options for the Library handling upon exporting and none of them fix the issue.

Can anyone explain this?

Answer 1

Setup Your Manifest

If I had to guess, your manifest doesn't contain your main class OR the classpath is not defined.

Main-Class: https://docs.oracle.com/javase/tutorial/deployment/jar/appman.html
Class-Path: https://docs.oracle.com/javase/tutorial/deployment/jar/downman.html

If you're using a build tool like maven, it needs to be configured to add these properties: https://maven.apache.org/shared/maven-archiver/examples/classpath.html

Execute Your Jar

There are two ways to run an executable jar. As an executable jar you need to define the Main-Class and Class-Path in your manifest:

java -jar YourJar.jar

You can also skip setting up your manifest and define your classpath and main class through the JVM's parameters.

java -cp=${PATH_TO_JAR} main.package.MainClass

Answer 2

I know I'm late, but I want to prevent people having to search hours for the same Error I just did. In Eclipse the path-String isn't case-sensitive. In the exported Runnable Jar File it is. So make sure all the pathsnames have the capital letters in the right positions, or to be save don't have capital letters at all.

Answer 3

Run it from the command line. This will allow you to see the exception that's thrown that's preventing your program from progressing.

java -jar YourJar.jar