Add support for java 21 for debian packages

[vishesh92]

Description

This PR adds support for java 21 in the debian packages for debian 13 & ubuntu 26.04

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• Build/CI
• Test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

How Has This Been Tested?

How did you try to break this feature and the system with this change?

[vishesh92]

@blueorangutan package

[blueorangutan]

@vishesh92 a [SL] Jenkins job has been kicked to build packages. It will be bundled with KVM, XenServer and VMware SystemVM templates. I'll keep you posted as I make progress.

[weizhouapache]

@blueorangutan package

[blueorangutan]

@weizhouapache a [SL] Jenkins job has been kicked to build packages. It will be bundled with KVM, XenServer and VMware SystemVM templates. I'll keep you posted as I make progress.

[weizhouapache]

Points to consider:

• Build JDK: the Build-Depends order puts openjdk-17-jdk ahead of openjdk-21-jdk. On a host with both installed, the build picks whichever apt resolves first. That’s probably fine, but it’s worth confirming which JDK the Debian 13 and Ubuntu 26.04 build actually uses.
• Remaining mysql.connector users: tools/marvin/marvin/dbConnection.py and some tools/docker files still use mysql.connector directly. They are test tooling, so this is probably out of scope, but they’ll have the same problem on these distros.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 18.03%. Comparing base (c7667d8) to head (0fada8d).

Additional details and impacted files

@@            Coverage Diff            @@
##               4.22   #14418   +/-   ##
=========================================
  Coverage     18.03%   18.03%           
- Complexity    16286    16289    +3     
=========================================
  Files          5937     5937           
  Lines        536771   536771           
  Branches      65782    65782           
=========================================
+ Hits          96787    96797   +10     
+ Misses       428932   428921   -11     
- Partials      11052    11053    +1     

Flag	Coverage Δ
uitests	4.04% <ø> (ø)
unittests	19.10% <ø> (+<0.01%)	⬆️

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[blueorangutan]

Packaging result [SF]: ✔️ el8 ✔️ el9 ✔️ el10 ✖️ debian ✖️ suse15. SL-JID 19578

[vishesh92]

Points to consider:

* Build JDK: the Build-Depends order puts openjdk-17-jdk ahead of openjdk-21-jdk. On a host with both installed, the build picks whichever apt resolves first. That’s probably fine, but it’s worth confirming which JDK the Debian 13 and Ubuntu 26.04 build actually uses.

On distros that ship both (e.g. Ubuntu 24.04), a fresh install still pulls OpenJDK 17 since it's the first alternative, so existing setups see no change. OpenJDK 21 is only used when it's the only one available (Debian 13) or already installed.

* Remaining mysql.connector users: tools/marvin/marvin/dbConnection.py and some tools/docker files still use mysql.connector directly. They are test tooling, so this is probably out of scope, but they’ll have the same problem on these distros.

I don't think we need to make any changes for this in the PR.

[vishesh92]

@blueorangutan package

[blueorangutan]

@vishesh92 a [SL] Jenkins job has been kicked to build packages. It will be bundled with KVM, XenServer and VMware SystemVM templates. I'll keep you posted as I make progress.

[blueorangutan]

Packaging result [SF]: ✔️ el8 ✔️ el9 ✔️ el10 ✔️ debian ✖️ suse15. SL-JID 19583

[weizhouapache]

lgtm

ubuntu26 and debian13 environments have been created successfully without extra step to install python3 connector

[wido]

I reviewed this manually and then used Claude Fable to check and build the PR.

Built the PR head on Temurin JDK 21.0.12 with -P developer,systemvm -Dsimulator -DskipTests. All modules build, including the UI, apidocs and marvin. Unit tests of utils, framework/db, engine/orchestration and the KVM plugin also pass on JDK 21 (the one QemuImgTest error is a missing libvirt.so on my machine).

Package side: Debian 13 ships neither openjdk-17 nor python3-mysql.connector, so there Java 21 and PyMySQL are the only options. Ubuntu 26.04 still has openjdk-17 and python3-mysql.connector 9.5.0, so a fresh install there keeps running on 17.

The PyMySQL fallback is API compatible with how the three scripts use the connection: single statements, explicit commit, ping and fetchall.

One point, following up on Wei's remark about the build JDK. debian/rules does not set JAVA_HOME, so the build runs on whatever update-alternatives selects, not on the first Build-Depends alternative. On Ubuntu 26.04 default-jre-headless is openjdk-25 and maven lists it as its first alternative. If openjdk-25 ends up on the build host, the build fails in cloud-utils on aspectjweaver 1.8.13 (zip64 header rejected by JDK 24+). I hit this on my own 26.04 machine. It would be safer if build-deb.sh or debian/rules exported JAVA_HOME to the newest of java-21 or java-17 under /usr/lib/jvm when present. Fine as a follow-up.

Nit: the description only mentions Java 21, but half of the PR is the PyMySQL fallback. Worth a line in the description and ticking a box in the template.

[wido]

CLGTM