java wont find class needed class in class path

Question

I have not run a non-jar java program directly from command line for ages, but now that i need it i'm having some problems, the program wont find the needed libs in the class path To reproduce my problem i have created the following, here's the code of the java file:

    package launcher;

import org.joda.time.DateMidnight;

public class Launcher {

    public static void main(String... args){
        DateMidnight mid=new DateMidnight();
        System.out.println(mid.dayOfMonth().toInterval());
    }
}

in my current directory under my user "on mac", i have only the following jar: joda-time-2.0.jar and the above .java file. I want to compile it and run it, so i do:

javac -d . -cp joda-time-2.0.jar Launcher.java 

I have now in my current folder the following:

Launcher.java       joda-time-2.0.jar   launcher 

Where launcher is a dir containing Launcher.class

Now if i run java -cp . launcher.Launcher java -cp . launcher.Launcher I get:

Exception in thread "main" java.lang.NoClassDefFoundError: org/joda/time/DateMidnight
at launcher.Launcher.main(Launcher.java:8)

Caused by: java.lang.ClassNotFoundException: org.joda.time.DateMidnight

i'm telling the vm where the compiled joda library is, whats wrong here?

Answer 1

You included the JAR in the javac call. But you called java only with the current directory in the classpath.

Try this:

java -cp .:joda-time-2.0.jar launcher.Launcher

Answer 2

Jars are treated as separate locations/directories, so . will not represent them. You need to explicitly add them to your classpath while you are compiling and running your code. Use something like

java -cp .;joda-time-2.0.jar launcher.Launcher 

or

java -cp .:joda-time-2.0.jar launcher.Launcher 

depending on which OS you are using.

You can also use *.jar wildcard if you have more jars you want to add.