[jira] [Created] (BEAM-1092) Shade commonly used libraries (e.g. Guava) to avoid class conflicts

["Maximilian Michels (JIRA)" <ji...@apache.org>]

Maximilian Michels created BEAM-1092:
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             Summary: Shade commonly used libraries (e.g. Guava) to avoid class conflicts
                 Key: BEAM-1092
                 URL: https://issues.apache.org/jira/browse/BEAM-1092
             Project: Beam
          Issue Type: Bug
          Components: examples-java, sdk-java-extensions
    Affects Versions: 0.3.0-incubating
            Reporter: Maximilian Michels
            Assignee: Frances Perry
             Fix For: 0.4.0-incubating


Beam shades away some of its dependencies like Guava to avoid user classes from clashing with these dependencies. Some of the artifacts, e.g. KafkaIO, do not shade any classes and directly depend on potentially conflicting libraries (e.g. Guava). Also, users might manually add such libraries as dependencies.

Runners who add classes to the classpath (e.g. Hadoop) can run into conflict with multiple versions of the same class. To prevent that, we should adjust the Maven archetypes pom files used for the Quickstart to perform shading of commonly used libraries (again, Guava is often the culprit).

To prevent the problem in the first place, we should expand the shading of Guava and other libraries to all modules which make use of these. 

To solve both dimensions of the issue, we need to address:

1. Adding shading of commonly used libraries to the archetypes poms
2. Properly shade all commonly used libraries in the SDK modules

2) seems to be of highest priority since it affects users who simply use the provided IO modules.



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