code: public boolean getBoolean(String key, boolean def) {
          String value = getString(key);
          if (value == null) {
              return def;
          }
          else {
              return "true".equalsIgnoreCase(value);
          }
      }
docs: Returns the default value if the given key isn't in this PropertyMap or
  if the the value isn't equal to "true", ignoring case.
  
  @param key Key of property to read
  @param def Default value