running scala apps with java -jar

Question

I got some problems with the java. Check it out.

sebastian@sebastian-desktop:~/scaaaaaaaaala$ java -cp /home/sebastian/.m2/repository/org/scala-lang/scala-library/2.8.0.RC3/scala-library-2.8.0.RC3.jar:target/scaaaaaaaaala-1.0.jar scaaalaaa.App

Hello World!

That's cool, right, but how bout this:

sebastian@sebastian-desktop:~/scaaaaaaaaala$ java -cp /home/sebastian/.m2/repository/org/scala-lang/scala-library/2.8.0.RC3/scala-library-2.8.0.RC3.jar -jar target/scaaaaaaaaala-1.0.jar

Exception in thread "main" java.lang.NoClassDefFoundError: scala/Application
 at java.lang.ClassLoader.defineClass1(Native Method)
 at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
 at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
 at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
 at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
 at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
 at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
 at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
 at scaaalaaa.App.main(App.scala)
Caused by: java.lang.ClassNotFoundException: scala.Application
 at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
 at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
 ... 13 more

Wat the heck? Any idea why the first works and not the 2nd? How do I -jar my scala??

My thanks in advance, brother.

Answer 1

If you define -jar the -classpath is ignored:

Java manual:

-jar When you use this option, the JAR file is the source of all user classes, and other user class path settings are ignored.

You can define the classpath dependencies in the Manifest metadata.

The easiest way to start your app is using the scala scripts:

scala -classpath target/scaaaaaaaaala-1.0.jar scaaalaaa.App Hello World!