code: public static Set<String> getPropertiesByPrefix(final String propertyNamePrefix) {
  
          Set<String> ret = new TreeSet<String>();
          Set<Object> keys = properties.keySet();
          for (Object key : keys) {
              if (null != key && key.toString().startsWith(propertyNamePrefix)) {
                  ret.add(properties.getProperty(key.toString()));
              }
          }
  
          return ret;
      }
docs: Get a set of properties those share the same given name prefix.
  
  @param propertyNamePrefix
  prefix of name
  @return the set of values whose property names share the same prefix