GeoJSONReader reader = new GeoJSONReader();
        File file = new ClassPathResource("plz-5stellig.geojson").getFile();
        String geoJsonString = Files.toString(file, Charset.defaultCharset());

        GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory();
        Coordinate coord = new Coordinate(52.516818, 13.383675);
        Point point = geometryFactory.createPoint(coord);

        FeatureCollection featureCollection = (FeatureCollection) GeoJSONFactory.create(geoJsonString);
        for (Feature feature : featureCollection.getFeatures())
        {
           Geometry geometry = reader.read(feature.getGeometry());
           boolean contains = geometry.contains(point);
        }