code: static String mapEntryToString(Object key, Object val) {
          final String k, v;
          final int klen, vlen;
          final char[] chars =
              new char[(klen = (k = objectToString(key)).length()) +
                       (vlen = (v = objectToString(val)).length()) + 1];
          k.getChars(0, klen, chars, 0);
          chars[klen] = '=';
          v.getChars(0, vlen, chars, klen + 1);
          return new String(chars);
      }
docs: Optimized form of: key + "=" + val