public static String formulateJsonForListQueriesCall(Region<String, String> queryRegion) {
    try (HeapDataOutputStream outputStream = new HeapDataOutputStream(KnownVersion.CURRENT)) {
      JsonGenerator generator = enableDisableJSONGeneratorFeature(getObjectMapper().getFactory()
          .createGenerator((OutputStream) outputStream, JsonEncoding.UTF8));
      JsonWriter.writeQueryListAsJson(generator, "queries", queryRegion);
      generator.close();
      return new String(outputStream.toByteArray());
    } catch (IOException e) {
      throw new RuntimeException(e.getMessage());
    }
  }
The JSONUtils class is a utility class for getting JSON equivalent from Java types.

@since GemFire 8.0
geode-web-api/src/main/java/org/apache/geode/rest/internal/web/util/JSONUtils.java