code: private Configuration getConfigurationInternal(final String[] keys) {
  
  		Configuration conf = new Configuration();
  
  		synchronized (this.confData) {
  
  			final Iterator<String> it = this.confData.keySet().iterator();
  
  			while (it.hasNext()) {
  
  				final String key = it.next();
  				boolean found = false;
  				if (keys != null) {
  					for (int i = 0; i < keys.length; i++) {
  						if (key.equals(keys[i])) {
  							found = true;
  							break;
  						}
  					}
  
  					if (found) {
  						conf.setString(key, this.confData.get(key));
  					}
  				} else {
  					conf.setString(key, this.confData.get(key));
  				}
  			}
  		}
  
  		return conf;
  	}
docs: Internal non-static method to return configuration.
  
  @param keys
  array of keys specifying the subset of pairs to copy.
  @return the {@link Configuration} object including the key/value pairs