Java beginner

[Ekal Kulkarni]

I am using Eclipse IDE to develop my application. I added pdfbox-1.0.0.jar
as a library jar. But when I try to use any class, I get exception:

code:
 public static void main(String[] args) {
  String mystr = org.apache.pdfbox.Version.getVersion();
  System.out.println(mystr);
 }

Exception:
Exception in thread "main" java.lang.NullPointerException
 at org.apache.pdfbox.Version.getVersion(Version.java:52)
 at Test1.main(Test1.java:10)

I am a beginner in java. Please help how to solve this.
-Ekal