code: public static String unescape( String jcrExpression ) {
          Objects.requireNonNull(jcrExpression);
          if (jcrExpression.indexOf('\\') < 0) {
              return jcrExpression;
          }
          final StringBuilder buf = new StringBuilder(jcrExpression.length());
  
          for (CharacterIterator iter = new StringCharacterIterator(jcrExpression); iter.current() != CharacterIterator.DONE; iter.next()) {
              if (iter.current() == '\\' && iter.next() == '\\') {
                  buf.append('\\');
                  continue;
              }
              buf.append(iter.current());
          }
          return buf.toString();
      }
docs: Removes {@code \}-triggered escape sequences from {@code jcrExpression}.
  @param jcrExpression {@link String}, never {@code null}
  @return {@link String}
  @since 5.5