Index: trunk/JavaHelperLib/src/de/ugoe/cs/util/console/CommandExecuter.java
===================================================================
--- trunk/JavaHelperLib/src/de/ugoe/cs/util/console/CommandExecuter.java	(revision 313)
+++ trunk/JavaHelperLib/src/de/ugoe/cs/util/console/CommandExecuter.java	(revision 320)
@@ -84,6 +84,12 @@
 	 * @param pkg
 	 *            package where commands are located
+	 * @throws InvalidParameterException
+	 *             thrown if the package name is null or empty string
 	 */
 	public void addCommandPackage(String pkg) {
+		if ("".equals(pkg) || pkg == null) {
+			throw new InvalidParameterException(
+					"package name must not be null or empty string");
+		}
 		commandPackageList.add(pkg);
 	}