Bootstrap class path not in conjuction

[Ryan Niemocienski <ni...@google.com.INVALID>]

Hey Beam,

I'm attempting to patch beam (PR here:
https://github.com/apache/beam/pull/3933) but am running into a warning
that I can't figure out the cause to. The warning is "bootstrap class path
not set in conjunction with -source 1.7" which, after some googling, seems
like it's an issue with building sources to target one java version while
using backwards incompatible features? I might be misunderstanding though.
Weirdly, "mvn clean verify" succeeds locally.

Posting here to see if anyone's run into this, or knows of a possible
solution.

Full build context here:
https://builds.apache.org/job/beam_PreCommit_Java_MavenInstall/14761/org.apache.beam$beam-sdks-java-io-google-cloud-platform/console

Re: Bootstrap class path not in conjuction

[Lukasz Cwik <lc...@google.com.INVALID>]

The build will succeed but it is possible that the artifacts that you built
won't actually work if run with JRE 7 for a few reasons (for example you
may have linked against a method that was added in a later version of the
JRE). This isn't a problem for a normal user because they typically are not
shipping the Apache Beam artifacts.

When cross compiling[1], you really need to set -source, -target,
-bootclasspath and -extdirs to get rid of this warning. Its very difficult
to actually set the -bootclasspath and -extdirs in a general Maven project
because we need to know that the user has the JDK of the specific version
installed. This is why we don't force it on users but instead have a post
commit test[2] that validates that the Java 7 modules build with JDK 7.

[1]:
https://github.com/apache/beam/blob/f9bc76364636b92239510f9e6bd242ea0ea62ac6/.test-infra/jenkins/job_beam_PostCommit_Java_JDKVersionsTest.groovy
[2]: http://docs.oracle.com/javase/7/docs/technotes/tools/windows/javac.html

On Tue, Oct 3, 2017 at 10:47 AM, Ryan Niemocienski <niemo@google.com.invalid
> wrote:

> Hey Beam,
>
> I'm attempting to patch beam (PR here:
> https://github.com/apache/beam/pull/3933) but am running into a warning
> that I can't figure out the cause to. The warning is "bootstrap class path
> not set in conjunction with -source 1.7" which, after some googling, seems
> like it's an issue with building sources to target one java version while
> using backwards incompatible features? I might be misunderstanding though.
> Weirdly, "mvn clean verify" succeeds locally.
>
> Posting here to see if anyone's run into this, or knows of a possible
> solution.
>
> Full build context here:
> https://builds.apache.org/job/beam_PreCommit_Java_
> MavenInstall/14761/org.apache.beam$beam-sdks-java-io-google-
> cloud-platform/console
>