Session-specific Java Reset

[Andraz]

We encountered an interesting issue with Java Native Interface (JNI) libraries in SQL Anywhere 17. Java version used is 8.
When deploying updated Java classes that use JNI, we need to handle JVM reinitialization.

Issue:
- Using a third-party Java library that utilizes JNI/SWIG bindings
- When updating Java classes in the database, the JNI initialization fails because it can only happen once per JVM lifecycle
- Database restart works but isn't ideal for production environments

Found that STOP JAVA and START JAVA (or STOP/START EXTERNAL ENVIRONMENT JAVA) commands work, but they're session-specific. This means:
- Works in current session
- New connections/sessions need their own STOP/START JAVA
- Different users need to execute these commands in their sessions

Is there a better way to manage Java restarts in a running database?
We are looking at any potential solutions or best practices in managing the external environment with a problem like this.

[VolkerBarth]

Just some wild guesswork, as I do not have used JAVA external environments myself:
In my understanding, the JAVA external environment (like CLR) does use one external instance per database (or even per database server), not per connection (in contrast, say, to the C external environments). Therefore, I would assume that STOP JAVA and or STOP EXTERNAL ENVIRONMENT do only shutdown the Java VM when the last connection is closed. That's what the docs tell on the STOP JAVA statement:

> The STOP JAVA statement unloads the ClassLoader for the current connection. If the current connection is the last connection using the Java VM, then the STOP JAVA statement will also exit the Java VM. The main use of the STOP JAVA statement is to economize on the use of system resources.