Issue compiling Hono

[ctron]

I noticed this a while back, but didn't really look into it, as it only sporadically popped up in a CI instance.

However now I run into this when deploying Hono 0.8 (the released version) on OpenShift. I didn't run into this before though.

Compiling Hono gives:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.7.0:testCompile (default-testCompile) on project hono-client: Compilation failure
[ERROR] /tmp/src/client/src/test/java/org/eclipse/hono/client/impl/CommandConnectionImplTest.java:[243,25] cannot find symbol
[ERROR]   symbol:   method close(io.vertx.core.Handler<io.vertx.core.AsyncResult<java.lang.Void>>)
[ERROR]   location: variable consumer of type java.lang.Object
[ERROR] -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.7.0:testCompile (default-testCompile) on project hono-client: Compilation failure
/tmp/src/client/src/test/java/org/eclipse/hono/client/impl/CommandConnectionImplTest.java:[243,25] cannot find symbol
symbol:   method close(io.vertx.core.Handler<io.vertx.core.AsyncResult<java.lang.Void>>)
location: variable consumer of type java.lang.Object

[ctron]

Adding the argument -Dmaven.test.skip=true to the maven build will work around this issue, as the test sources don't get compiled.

[ctron]

I actually can reproduce this locally when doing mvn clean test in the client directory.

Running with Java:

openjdk version "1.8.0_191"
OpenJDK Runtime Environment (build 1.8.0_191-b12)
OpenJDK 64-Bit Server VM (build 25.191-b12, mixed mode)

[ctron]

Same result with:

java version "1.8.0_151"
Java(TM) SE Runtime Environment (build 1.8.0_151-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.151-b12, mixed mode)

[sophokles73]

We are running into the same issue. However, since the code seems to be correct (at least nobody who took a look so far could find something suspicious), I would attribute this to the (growing) list of issues with OpenJDK 8 ... I (we at Bosch) have moved on to OpenJDK 11.0.1 which behaves as expected ...

[ctron]

I agree that this could be the issue. That would also explain why this isn't an issue with the Eclipse IDE, as it uses ECJ instead of javac.

On the other side, we did promise support for Java 8 in Hono 0.8, and so I would like to fix at least the deployment scripts for OpenShift S2I, adding this particular Maven switch. But this would need to be done in the branch of 0.8.x. We wouldn't need to re-release though, as this is only the template file.

[sophokles73]

On the other side, we did promise support for Java 8 in Hono 0.8

The binaries can be run with a version 8 JVM. The problem is only with compiling.

But this would need to be done in the branch of 0.8.x.

Then by all means, create the branch 👍

[Alfusainey]

I would attribute this to the (growing) list of issues with OpenJDK 8

Just a side note: i was also facing the same issue compiling the sources with Oracle JDK 8. so probably the issue is not specific to OpenJDK

[ctron]

I agree, I think this is an issue with OpenJDK(-based) javac. The ECJ is more powerful, as least from what I experienced (javac developers might disagree). As the Oracle JDK is based on OpenJDK, it provides the some issues as OpenJDK 😁

Moving on to Java 11 might be the right thing to do here. But we should, to some degree, support users of Java 8, as said to support Hono 0.8 with that.

Anyway, I think the issue is solved for the S2I based deployment when #934 is merged.

[sophokles73]

@ctron can we (you) close this issue?

[ctron]

Well the issue is not solved in general … for OpenShift S2I, we have a workaround.

The question is do we really want to solve this, or simply go for Java 11 and ignore it … I would have no issues going for the latter.

[sophokles73]

How could we resolve an issue with OpenJDK? FMPOV we have a workaround for Hono altogether, which is to use OpenJDK 11 for compiling ...

So +1 for going to Java 11, which we already have done

[ctron]

We could re-write that section to make it "compliant" with the OpenJDK 8 javac … but I would prefer not to do this.

It looks like fabric8io-images/s2i#203 is near completion … let's move on to Java 11 and don't look back. And if someone has a complaint, re-open the issue.