Transient dependency on Guava 16 prohibits higher-level code moving to Guava 21

[lukeu]

The crash one sees when putting Guava 21 on the classpath is the following:

java.lang.NoSuchMethodError: com.google.common.base.Objects.firstNonNull(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
  at com.github.fge.jackson.JsonLoader.fromResource(JsonLoader.java:83
  ....

Guava 21 is appealing because it adds a number of very useful utilities for working with Java 8. However in this release, they have (after a period of planned deprecation) removed methods from their Objects class (due to Java 8 containing an Objects class).

I understand jackson-coreutils may wish to retain support for Java 6. Fortunately, Guava planned ahead and there is a window of cross-over:

A solution may be for jackson-coreutils to depend on Guava 18, 19 or 20. These all contain the class MoreObjects as a duplicate of Objects from Guava 16. So it may just be a matter of bumping the Guava version and substituting Objects with MoreObjects. Upstream code can then use Guava 21+ (which still contains these methods in MoreObjects)

An alternative might be to just inline the calls to the utility functions in Objects, if they are not used too frequently.

Related:

• Issue Consider moving off Google Guava #8
• Pull request Enforce OSGI Import-Package of guava libraries to use version >=16 && < 19, to allow using with latest Guava #5

[lukeu]

Here's a 4-line patch that seems to do the trick. (One line of Java changed, and no other deprecation warnings found after updating to Guava 20.)

0001-Update-Guava-from-16.0.1-20.0.patch.zip

[mjsmith707]

Is this ever going to get merged? We're on Guava 23 now

[lukeu]

Have just created (my first ever) Pull Request. Hopefully this is trivial & risk-free enough to be picked up by the project maintainer.

[lukeu]

@huggsboson I notice that you've helped the community get some pull requests into json-schema-validator by taking it under the java-json-tools umbrella ("organisation").

I don't suppose you'd consider doing the same with this dependency of that project? (It's included via json-schema-validator). Unfortunately these projects all reference an old version of Guava which blocks higher-level projects from upgrading Guava due to a binary incompatibility. (Guava 23 is out now.) However I've made a minimalistic pull request here (#13) that would resolve this, which still allows these projects to continue to reference Guava 16 if they wish.

(Although I believe, without any Android experience myself, that it should be possible to upgrade them all to reference Guava 20 without breaking Android and Java 6 support.)