Restore support for Java 8

[dbw9580]

The recent 1.3.2 release raised target Java version from 8 to 11. However, some project I'm working on is still on Java 8, and I believe many existing projects out there are not ready to upgrade to 11 yet.

I find that the only place where Java 11 features were used was in the tests. This PR replaces them with Java 8 compatible implementation and reverts minimum required Java version to 8. Please consider staying compatible with Java 8 for a bit longer!

[lidel]

Mind taking a look @ianopolous?

IIUC this is a small change that could unblock Java 8 projects, as noted in apache/drill#2084 (comment)

ps. I noticed CI does not run tests on PRs made from forks, proposed fix in #173

[lidel]

Thanks!
@dbw9580 will this just work for you, or do you need a new release?

[dbw9580]

Thanks! @lidel A v1.3.3 would be nice.

[lidel]

@ianopolous how does releasing to Jitpack work? Will creating v1.3.3 tag and new release on github be enough?

[ianopolous]

Hi @lidel That is documented in the other Java repos, we should add the same comment to this repo's readme:
https://github.com/multiformats/java-multibase#releasing

[dbw9580]

@ianopolous @lidel Hi, will a v1.3.3 release be available soon? We are preparing to merge the PR of Drill, it would be nice to be able to use the "offcial" release from the IPFS community.

[lidel]

@dbw9580 just tagged v1.3.3 – please give it a try and let us know if any issues :-)