docs: public static boolean initializeUnescapePattern() {
          if (paternIsInitialized == true) {
              return true;
          }
  
          synchronized (unescapeInitLockObject) {
              if (paternIsInitialized == true) {
                  return true;
              }
  
              try {
                  unescapePattern = Pattern.compile(unicodeUnescapeMatchExpression);
              } catch (PatternSyntaxException pse) {
                  /*
                   * the pattern is compiled from a final string, so this
                   * exception should never be thrown
                   */
                  System.err.println("Imposible error:  " + "static final regular expression pattern "
                          + "failed to compile.  Exception:  " + pse.toString());
                  return false;
              }
              paternIsInitialized = true;
          }
          return true;
      }