Re: [libvirt] [PATCH libvirt-java] Require at least Java 8

At Wed, 2 Sep 2015 17:38:03 +0200, Wido den Hollander wrote: > > > >> The current code doesn't compile under Java 7, but Java 7 is also EOL. >> >> >> That should not be the case. Can you provide the error messages or >> simply point to the place where Java 8 classes are used? >> > > build: > [javac] Compiling 98 source files to > /home/wido/repos/libvirt-java/target/classes > [javac] warning: [options] bootstrap class path not set in > conjunction with -source 1.7 > [javac] > /home/wido/repos/libvirt-java/src/main/java/org/libvirt/event/DomainEvent.java:63: > error: incompatible types: inference variable T#1 has incompatible upper > bounds Enum<T#2>,T#3 > [javac] return this.type.obtain(this.detail); > [javac] ^ > [javac] where T#1,T#2,T#3 are type-variables: > [javac] T#1 extends Enum<T#1> declared in method <T#1>obtain(int) > [javac] T#2 extends T#3 > [javac] T#3 extends Enum<T#3>,DomainEventDetail declared in > method <T#3>getDetail() > [javac] 1 error > [javac] 1 warning This reminded me of a problem I once saw with the Java 7 (I think) compiler being unable to correctly infer the types when calling static generic methods. Since I always used the Java 7 compiler to compile the code and as I saw the javac warning above, I got curious. The thing is: the code compiles just fine with an actual Java 7 compiler (OpenJDK 1.7.0_85), but not when using a Java 8 compiler (OpenJDK 1.8.0_60) with the `-source 1.7` switch.

> But if the compile issue can be fixed we can probably require at least > Java 7. I think Java 6 is dangerous. I'm still thinking about this. Maybe you're right. But still, the code is valid 1.7 source code. Should we prevent that code from compiling on Java 7 to protect users from using an obsolete JVM? I don't think this is the right place to control that.

-- Claudio