code: public static String getStringProperty(@Nonnull LogManager manager, @Nullable String name, String defaultValue) {
          if (name == null) {
              return defaultValue;
          }
          String val = manager.getProperty(name);
          if (val == null) {
              return defaultValue;
          }
          return val.trim();
      }
docs: Visible version of {@link java.util.logging.LogManager#getStringProperty(String, String)}.
  
  If the property is not defined we return the given default value.