Problem with running java project from a command line

Question

I have a JavaFX project with two classes and one external library. When I run it from IDE (IntelliJ Idea) - everything works well. But when i run it from command line using command:

java Main

the program starts, but when I try to use the functionality associated with the external library, i have an exception:

Exception in thread "Thread-4" java.lang.NoClassDefFoundError: com/google/gson/Gson

Why does everything work well when I run it through IDE, and when I run it through the console, it stops seeing the library Gson?

Ross · Accepted Answer · 2019-03-31 17:54:05Z

1

When you run your program from your IDE, like IntelliJ or eclpse, it's probably including the external jars automatically to it's own the classpath for you, depending on your setup.

If you want to run it from the command line you'll need to add the gson jar to your classpath using the -classpath argument.

java -classpath external-library.jar Main

Reference:

Windows - https://docs.oracle.com/javase/8/docs/technotes/tools/windows/classpath.html

Unix - https://docs.oracle.com/javase/8/docs/technotes/tools/unix/classpath.html

answered Mar 31, 2019 at 17:54

Ross

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bvl Over a year ago

Thank you! My command is: java -classpath "path_to_library.jar;path_to_class\" Main

riorio · Accepted Answer · 2019-04-01 05:59:44Z

1

Most common reason will be that your Gson library isn't exported when you create your jar.

When the IDE runs your code it can find it. But when you export it to a JAR and it doesn't contain the relevant dependencies, you will get this error.

edited Apr 1, 2019 at 5:59

answered Mar 31, 2019 at 17:15

riorio

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