How to work with Scala and Jcurses?

Question

I want to use Jcurses with Scala on a 64-bit Ubuntu. Unfortunately i didn't find any tutorial about this subject. Can anybody help me!

My test program "testjcurses.scala"

import jcurses.system._
object TestJcurses {
  def main(args:Array[String]) {
    println("okay")
    Toolkit.init()
    }
  }

I processed it the following way:

fsc -cp ~/software/Java/jcurses/lib/jcurses.jar:~/software/Java/jcurses/src -d . -Djava.library.path=~/software/Java/jcurses/lib testjcurses.scala 
scala -cp ~/software/Java/jcurses/lib/jcurses.jar:~/software/Java/jcurses/src:.  -Djava.library.path=~/software/Java/jcurses/lib  TestJcurses

The result is:

okay
java.lang.NullPointerException
    at jcurses.system.Toolkit.getLibraryPath(Toolkit.java:97)
    at jcurses.system.Toolkit.<clinit>(Toolkit.java:37)
    at TestJcurses$.main(testjcurses.scala:9)
    at TestJcurses.main(testjcurses.scala)
   ..........

Can anybody help me?

I used java long time ago. It will take some time to perform this task. — pommfritz, Aug 17 '14 at 21:41
By the way, your sample code runs fine on my machine—although it took some effor to fix the JCurses makefile to build on OS X. There's just something wrong with your setup. — DaoWen, Aug 18 '14 at 00:52
JCurses is likely not finding the library, since the stack trace shows a failure in `getLibraryPath`. Below my best guess. — Blaisorblade, Aug 24 '14 at 07:53
@pommfritz: if you like the answer, could you please also upvote it? Thanks. — Blaisorblade, Aug 30 '14 at 09:41
@Blaisorblade: I'm sorry I don't have the required reputation yet to do so. — pommfritz, Aug 31 '14 at 11:36

score 1 · Accepted Answer · answered Aug 24 '14 at 07:52

Unfortunately you can't use ~ in bash like that — ~ is expanded to your home dir only right after an (unquoted) space (technically, at the beginning of a bash word, but "after a space" is the simple version). Look how your command line is expanded:

$ echo scala -cp ~/software/Java/jcurses/lib/jcurses.jar:~/software/Java/jcurses/src:.  -Djava.library.path=~/software/Java/jcurses/lib  TestJcurses
scala -cp /Users/pgiarrusso/software/Java/jcurses/lib/jcurses.jar:~/software/Java/jcurses/src:. -Djava.library.path=~/software/Java/jcurses/lib TestJcurses

As you can see, the ~ is there in the expanded version, and will arrive unchanged to your program, which will be unable to interpret it as anything since tilde expansion is a job for the shell.

Also, you shouldn't need the source directory ~/software/Java/jcurses/src in your classpath (since source files aren't needed to run the program). So try:

scala -cp ~/software/Java/jcurses/lib/jcurses.jar:. -Djava.library.path=$HOME/software/Java/jcurses/lib  TestJcurses

How to work with Scala and Jcurses?

1 Answers1