STEP: Create Dynamic Web Project with JAX-RS Support STEP: Create the following classes public class Car { public String brand; public String getBrand() { return brand; } public void setBrand( String brand) { this .brand = brand; } } @Path( "/" ) public class Resource { @POST @Path( "{car}" ) public void post(@PathParam( "car" ) Car car) { } } ASSERT: There is an JAX-RS Problem because of the invalid parameter STEP: Create class that implements ParamConverterProvider @Provider public class Converter implements ParamConverterProvider { private ParamConverter<Car> carConverter = new ParamConverter<Car>() { @Override public Car fromString( String arg0) { Car car = new Car(); car.setBrand(arg0); return car; } @Override public String toString(Car arg0) { return arg0.getBrand(); } }; @Override public <T> ParamConverter<T> getConverter( Class <T> arg0, Type arg1, Annotation[] arg2) { if (arg0.equals(Car.class)) { return (ParamConverter<T>) carConverter; } return null ; } } ASSERT: The JAX-RS Problem disappeared FAIL: The JAX-RS Problem is still present