How to solve the problem of 404 not found?

I am learning to develop with rest when I put the URL I always had HTTP status 404 - Not found Type Status report message The requested resource [/ jaxres-4sae5 / api / greetings / hello] is not available description The requested resource is not available. and I did not know the problem.

@Path("greetings")
public class HelloResource {
    @Path("hello")
    @GET
    @Produces(MediaType.TEXT_PLAIN)
    
    public String sayHello() {
        
        return "Hello from JAX-RS";
    }
    @GET
    @Path("{firstName}/{LastName}")
    @Produces(MediaType.TEXT_PLAIN)
    public String sayhello2( @PathParam(value="lastName")String nom, @PathParam(value="firstName")String prenom) {
        return "hello from JAXRS" + prenom +" "+ nom;
        }
    
    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String sayHelloTo2(@QueryParam(value="FirstName") String prenom ,
            @QueryParam(value="LastName")  String nom   ) {
                return "hello from JAXRS" + prenom + " " + nom;
        
    }