Compiling Sample files

[Regala]

Hi folks, I'm trying to compile and run Sample1.java file. Unfortunately I've stumbled upon the following error, after mvn install succeeds:

cd pentaho-reporting/assemblies/samples ; /usr/bin/env "/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java" -agentlib:jdwp=transport=dt_socket,server=n,suspend=y,address=localhost:63377 -Dfile.encoding=UTF-8 -cp /var/folders/6v/m75gjsgx3j73y1dmspwfv8t80000gn/T/cp_asosgqa4nbz5a26p93vd45pld.jar org.pentaho.reporting.engine.classic.samples.Sample1 
Exception in thread "main" java.lang.NullPointerException: Key data must not be null.
        at org.pentaho.reporting.libraries.resourceloader.DefaultResourceManagerBackend.createKey(DefaultResourceManagerBackend.java:49)
        at org.pentaho.reporting.libraries.resourceloader.ResourceManager.createKey(ResourceManager.java:141)
        at org.pentaho.reporting.libraries.resourceloader.ResourceManager.createKey(ResourceManager.java:128)
        at org.pentaho.reporting.libraries.resourceloader.ResourceManager.createDirectly(ResourceManager.java:199)
        at org.pentaho.reporting.engine.classic.samples.Sample1.getReportDefinition(Sample1.java:61)
        at org.pentaho.reporting.engine.classic.samples.AbstractReportGenerator.generateReport(AbstractReportGenerator.java:149)
        at org.pentaho.reporting.engine.classic.samples.AbstractReportGenerator.generateReport(AbstractReportGenerator.java:122)
        at org.pentaho.reporting.engine.classic.samples.Sample1.main(Sample1.java:115)

Since the default file didn't work I edited the classloader.getResource line and pointed the absolute file to the .prpt file, but it also fails.

Any hint on what the problem might be?

Cheers!