java.util.ServiceLoader not loading my provider class -

i trying put basic spi-based registry of handlers, lookup handlerregistry. when use serviceloader.load(handler.class) initialize providers, , iterate list lazily load them, not seeing instances of class. keeping simple possible, handlerregistry class is:

public class handlerregistry  {   private static handlerregistry registry;    private serviceloader<handler> handlerloader;    private handlerregistry()   {     handlerloader = serviceloader.load(handler.class);   }    public static synchronized handlerregistry getregistry()   {     if (registry == null) {       registry = new handlerregistry();       registry.init();     }     return registry;   }    private void init()   { system.out.println("handlerregistry.init()");   }    public handler lookup(string item)   { system.out.println("lookup("+item+")");     try {       iterator<handler> = handlerloader.iterator();       while (it.hasnext()) {         handler handler = it.next(); system.out.println("found handler "+handler);       }     }     catch (serviceconfigurationerror err) {       err.printstacktrace();     }     return null;   } } 

i have com.example.handler.handler interface (empty simplicity), , com.example.handler.handlers.dummyhandler class implements interface. have created file in jar called meta-inf/services/com.example.handler.handler, contains single line

com.example.handler.handlers.dummyhandler 

according javadoc. unit test calls lookup() method verify looking handler item. of course there eventulaly need check of kind see if right handler item, @ point not seeing dummyhandler class loaded registry. doing wrong here?

thanks!

the answer appears in sensitivity how configured. had been placing provider name resource file (the 1 named com.example.handler.handler) directly in top level project directory, i.e., /resources/meta-inf/services/com.example.handler.handler. had configured build.gradle pull file out , put jar:

jar { from('resources') { include 'meta-inf/services/*.*' } } 

when inspected jar file, file there, right expected be, thought well. on kick, happened move resources folder down under src/main, , presto! works. inspected jar file , appears identical 1 built previous way, reason 1 works. update further if can determine difference, @ least test case works now.