Geertjan, Emi and Boris, Many thanks for responding. It seems that Lookup and ServiceLoader are similar, yet different enough to be troublesome. I will need to do more testing, but first I will try to inject the services I need via a method, and not via META-INF/resources. Much appreciated. -Damian
On Sat, 17 Aug 2019 at 21:38, Boris Heithecker <boris.heithec...@gmx.net> wrote: > Are you sure that the services your third-party jar wants to look up via > java.util.ServiceLoader.load(Clazz.class) are registered as > META-INF/services entries? > The problem could be that Lookup.getDefault().lookup(Clazz.class) also > looks up services registered in the system file system (layer.xml) in the > /Services subdirectory. > Also, are you sure that your third-party jar does not specify a particular > class loader it finds appropriate when looking up up the service, i.e. > using the method signature java.util.ServiceLoader.load(Clazz.class, > MyLoader.class)? In the default case, > java.util.ServiceLoader.load(Clazz.class) uses > Thread.currentThread().getContextClassLoader() to look up the required > service, but this may be jdk implementation dependent. > Does your external jar require the service at an early phase during > start-up? The implementing module may not be fully ready yet. > Also, make sure no attempt is made to double load the service interface > class from two different classloaders. The NetBeans classloader system > allows, in principle, multiple definitions of the same class with the same > qualified name. But these are not available on the context classloader. > Look through the logs, you get it warning saying something like ".. won't > arbitrarily load class x from class loader y and z". > Maybe this helps. > Boris > > > On Sat, 17 Aug 2019 at 08:12, Damian Carey <jami...@gmail.com> wrote: > >> Hi all, >> >> We have a "mature" (10+ year old) Netbeans Platform Swing product, which >> has 35+ modules. This all works well. >> >> As usual, when one Netbeans module provides an Implementation we find it >> from other Netbeans modules using the usual idiom ... >> Provider: puts entry in META-INF/services >> Consumer: MyClass myObj = Lookup.getDefault().lookup(MyClass.class); >> >> Our current issue is that we need to add an external jar that is NOT >> built using Netbeans, so it can't use Lookup. I have placed this external >> jar into a module wrapper, and one of our modules depends on it so we can >> successfully start this service as appropriate. Again, everything is >> perfect with this setup. >> >> The problem is that this external jar is looking for services from our >> Netbeans platform product, it is seeking them using standard java >> ServiceLoader capability, but the implementations are not found. >> >> I *think* that if we use the Netbeans System ClassLoader then it CAN >> locate the implementations, however we don't want to use the system >> classloader because it will cause other issues. >> >> Does anyone have any suggestions on how a wrapped jar might access >> Netbeans META-INF/services implementations via vanilla Java ServiceLoader >> SPI interface? >> >> Any suggestions would be hugely appreciated. >> >> Many thanks, >> -Damian >> > > > -- > Boris Heithecker > > > Dr. Boris Heithecker > Lüneburger Str. 30 > 28870 Ottersberg > Festnetz: +49 4205 315834 > Mobil: +49 170 6137015 >
