private static String assertNotEmpty(String str, String name) {
    return assertNotEmpty(str, name, null);
  }
Check that a string is not null and not empty. If null or empty 
throws an IllegalArgumentException.

@param str value.
@param name parameter name for the exception message.
@return the given value.
hcatalog/webhcat/svr/src/main/java/org/apache/hive/hcatalog/templeton/ProxyUserSupport.java