java - Configuration class that extends Application in REST -

the class extends application in rest

import javax.ws.rs.applicationpath; import javax.ws.rs.core.application; import java.util.arrays; import java.util.hashset; import java.util.set;  @applicationpath("/rest-prefix") public class applicationconfig extends application {     public set<class<?>> getclasses() {         return new hashset<class<?>>(arrays.aslist(simplerestpojo.class, simplerestejb.class));     } } 

what's function? why should extend application class class nothing?

if don't, ide throws warning on rest classes, warning doesnt implement jersey or ee services.

whay should extend application class, , tutorials without other explanation.

thank you.