SQOOP-3441 Prepare Sqoop for Java 11 support

[fszabo2]

Contains the following minor fixes that came up when executing tests with java11:

• Bumped gradle version from 4.9 to 5.3.1 (needed for jacoco plugin)
• Fixed illegal access of constructor in a TestSqoopOptions
• Removed the use of UrlClassLoader as it wasn't needed anyway (Accumulo mini cluster startup)

[szvasas]

Hi Feró,

Thanks for submitting this improvement, unfortunately I don't have time to post a full review just had one comment on the Gradle upgrade.
Since we have the following wrapper task defined in build.gradle I think it would be good to maintain the version number in it:

wrapper {
    gradleVersion = '4.9'
}

Then running ./gradlew wrapper to make sure everything is fully updated to the version specified.
There are also some guidelines provided here: https://docs.gradle.org/current/userguide/gradle_wrapper.html#sec:upgrading_wrapper

(We could also remove the wrapper task and just run ./gradlew wrapper --gradle-version <version> in the future.)

[fszabo2]

Hi @szvasas,
Thanks for pointing this out!
I ran the command ./gradlew wrapper --gradle-version 5.3.1, and then force pushed as I also noticed a typo in the decription and wanted to correct that as well.

In any case, this is a proper upgrade now, albeit to 5.3.1 that is a deprecated version. I just realized this, I'll update the version to 5.4.1, if all tests pass that is the version we should use, it's the currently supported one.

Not sure why Oracle tests failed...

[ebogi]

Hi Fero, many thanks for preparing Sqoop for JDK 11 support! Your change LGTM but could you please update documentation (e.g. COMPILING.adoc) too? Thanks!

[fszabo2]

Hi @ebogi,
Thanks for the review! I've updated the version in COMPILING.adoc, automatic tests should pass all the same.

[ebogi]

Thanks for the doc update! Ship it!