On Apr 3, 2017, at 10:11 AM, Ron Sigal <rsigal(a)redhat.com&gt; wrote: ... So, it seems that, for lambdas, Java doesn't keep the implementation type and value of the type variable at run time. Does anyone have any ideas or tricks?

Hi Steven, That's really interesting. It works for both Oracle JDK 1.8.0_91 and JDK 9 build 163 from java.net. !! One problem I see is that Jonathan Halterman's TypeResolver class has the line > String constantPoolName = JAVA_VERSION < 9 ? > "sun.reflect.ConstantPool" : "jdk.internal.reflect.ConstantPool"; so I don't think we could use it for any JDK < 9. Once JDK 9 stabilizes and Resteasy is releasing JDK 9 code, maybe it would be OK. Even better would be if Class.getGenericInterfaces() were to work in JDK 9, but, as of build 163, it doesn't. In any case, you've helped to verify that the solution requires external tricks. Let's hope that your "right approach" is followed. Thank you very much, Ron On 04/03/2017 01:49 PM, Steven Schlansker wrote: >> On Apr 3, 2017, at 10:11 AM, Ron Sigal <rsigal(a)redhat.com&gt; wrote: >> ... >> >> So, it seems that, for lambdas, Java doesn't keep the implementation type >> and value of the type variable at run time. Does anyone have any ideas or >> tricks? > I did not have time to play with it myself, but I did run across this: > https://stackoverflow.com/questions/23863716/java-how-to-resolve-generic-... > maybe that helps? > > It sounds like the "right approach" would be to request Java stash the type > information better for lambdas... > -- My company's smarter than your company (unless you work for Red Hat) _______________________________________________ resteasy-dev mailing list resteasy-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/resteasy-dev

When I run > @Test > public void test2() > { > MapFunction<String, Integer> fn = str -> Integer.valueOf(str); > Class<?>[] typeArgs = > TypeResolver.resolveRawArguments(MapFunction.class, fn.getClass()); // > Using Jonathan Halterman's TypeResolver > System.out.println("typeArgs.length: " + typeArgs.length); > for (Class<?> clazz : typeArgs) > { > System.out.println(clazz); > } > } with openjdk 8, I get > typeArgs.length: 2 > class java.lang.String > class java.lang.Integer but when I run it with IBM jdk 8, I get > typeArgs.length: 2 > class org.jboss.resteasy.test.contextresolver.TypeResolver$Unknown > class org.jboss.resteasy.test.contextresolver.TypeResolver$Unknown I see that IBM jdk 8 has sun.reflect.ConstantPool, but that doesn't seem to be enough. I think we should revisit this issue when JDK 9 is released. It's probably too late to make a request, right?

-Ron On 04/07/2017 02:54 AM, Rostislav Svoboda wrote: > https://github.com/jhalterman/typetools#on-lambda-support > > Lambda type argument resolution is currently supported for: > Oracle JDK 8 > Open JDK 8 > > IBM JDK 8 will need some attention too. > > Rostislav > > ----- Original Message ----- >> Hi Steven, >> >> That's really interesting. It works for both Oracle JDK 1.8.0_91 and JDK >> 9 build 163 from java.net. !! >> >> One problem I see is that Jonathan Halterman's TypeResolver class has >> the line >> >>> String constantPoolName = JAVA_VERSION < 9 ? >>> "sun.reflect.ConstantPool" : "jdk.internal.reflect.ConstantPool"; >> so I don't think we could use it for any JDK < 9. Once JDK 9 stabilizes >> and Resteasy is releasing JDK 9 code, maybe it would be OK. >> >> Even better would be if Class.getGenericInterfaces() were to work in JDK >> 9, but, as of build 163, it doesn't. >> >> In any case, you've helped to verify that the solution requires external >> tricks. Let's hope that your "right approach" is followed. >> >> Thank you very much, >> >> Ron >> >> On 04/03/2017 01:49 PM, Steven Schlansker wrote: >>>> On Apr 3, 2017, at 10:11 AM, Ron Sigal <rsigal(a)redhat.com&gt; wrote: >>>> ... >>>> >>>> So, it seems that, for lambdas, Java doesn't keep the implementation >>>> type >>>> and value of the type variable at run time. Does anyone have any ideas >>>> or >>>> tricks? >>> I did not have time to play with it myself, but I did run across this: >>> https://stackoverflow.com/questions/23863716/java-how-to-resolve-generic-... >>> maybe that helps? >>> >>> It sounds like the "right approach" would be to request Java stash the >>> type >>> information better for lambdas... >>> >> -- >> My company's smarter than your company (unless you work for Red Hat) >> >> _______________________________________________ >> resteasy-dev mailing list >> resteasy-dev(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/resteasy-dev >> -- My company's smarter than your company (unless you work for Red Hat)

On Mon, Apr 10, 2017 at 10:15 AM, Rostislav Svoboda <rsvoboda(a)redhat.com <mailto:rsvoboda@redhat.com>> wrote: I would say so, there was some deadline for proposals till the end of 2016 and planned release of Java 9 is July 2017. Tomaz - any comment on this ? Yes, JDK9 is feature complete, but that doesn't prevent anyone to file a bug against it. Things that are considered bugs might still catch the GA release. -- tomaz _______________________________________________ resteasy-dev mailing list resteasy-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/resteasy-dev

On Mon, Apr 10, 2017 at 2:44 PM, Ron Sigal <rsigal(a)redhat.com <mailto:rsigal@redhat.com>> wrote: Thanks, Tomaž. Where is that bug list? http://bugreport.java.com/

FYI, I've filed a bug report. I'll let you know what, if any, response I get. On 04/10/2017 09:31 AM, Tomaž Cerar wrote: > > On Mon, Apr 10, 2017 at 2:44 PM, Ron Sigal <rsigal(a)redhat.com > <mailto:rsigal@redhat.com>> wrote: > > Thanks, Tomaž. Where is that bug list? > > > > http://bugreport.java.com/ -- My company's smarter than your company (unless you work for Red Hat) _______________________________________________ resteasy-dev mailing list resteasy-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/resteasy-dev

From: "Ron Sigal" <rsigal(a)redhat.com&gt; To: resteasy-dev(a)lists.jboss.org Sent: Monday, April 3, 2017 1:11:38 PM Subject: [resteasy-dev] Lambda question This question arises in https://issues.jboss.org/browse/RESTEASY-1209 "org.jboss.resteasy.util.Types#getActualTypeArgumentsOfAnInterface not working for lambda's." The reporter wants to do this: ResteasyProviderFactory factory = new ResteasyProviderFactory(); factory.register((ContextResolver<String>) type -> "foo bar"); but it doesn't work. I find that if I do this: ContextResolver<String> resolver1 = new ContextResolver<String>() { @Override public String getContext(Class<?> type) { return null; } }; for (Type type : resolver1.getClass().getGenericInterfaces()) { System.out.println(type); } I get javax.ws.rs.ext.ContextResolver<java.lang.String> but if I do ContextResolver<String> resolver2 = type -> "foo"; for (Type type : resolver2.getClass().getGenericInterfaces()) { System.out.println(type); } I get interface javax.ws.rs.ext.ContextResolver Same with ContextResolver<String> resolver2 = ((ContextResolver<String>)type -> "foo"); So, it seems that, for lambdas, Java doesn't keep the implementation type and value of the type variable at run time. Does anyone have any ideas or tricks? Thanks, Ron -- My company's smarter than your company (unless you work for Red Hat) _______________________________________________ resteasy-dev mailing list resteasy-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/resteasy-dev