Enable using PKCS#12 based Java keystores

[modulo11]

Summary

• Part of Java 18 Error - unable to decode keystore #158
• Abstracts operations on Java keystores by introducing an interface for common operations
• Minimum API, closely alight to previous implementation

Use Cases

• Re-enables adding ca-certificates to the Java keystore for Java 18 and above

Checklist

• I have viewed, signed, and submitted the Contributor License Agreement.
• I have linked issue(s) that this PR should close using keywords or the Github UI (See docs)
• I have added an integration test, if necessary.
• I have reviewed the styleguide for guidance on my code quality.
• I'm happy with the commit history on this PR (I have rebased/squashed as needed).

[dmikusa]

Code looks great! Thanks for putting this together. Just one question for you.

In the meantime, I'm going to give this a try with a few buildpacks and see how it runs.

[dmikusa]

Tested with Bellsoft buildpack:

• current version with Java 21 displays warning and does not load certs at runtime
• new version of libjvm same buildpack version with Java 21, loads certs at build time and runtime (no warning)
• new version of libjvm same buildpack version with Java 17, works as it did before
• looks correct

Tested with Adoptium, same behavior. Working correctly.

Tested with Azul Zulu, same behavior. Working correctly.

I'm happy with the testing.

@modulo11 did you test with the sap-machine buildpack?
@anthonydahanne or @pivotal-david-osullivan do you want to test this as well? or good to merge?

[modulo11]

@modulo11 did you test with the sap-machine buildpack? @anthonydahanne or @pivotal-david-osullivan do you want to test this as well? or good to merge?

Yes, tested locally with SapMachine and seems to work nicely.