code: public static boolean getBoolean(Properties config, String key, boolean defaultValue) {
  		String val = config.getProperty(key);
  		if (val == null) {
  			return defaultValue;
  		} else {
  			return Boolean.parseBoolean(val);
  		}
  	}
docs: Get boolean from properties.
  This method returns {@code true} iff the parsed value is "true".
  
  @param config Properties
  @param key key in Properties
  @param defaultValue default value if value is not set
  @return default or value of key