[WIP] First attempt at fixing second jabref instance detection

[Siedlerchr]

Detection works now , but there remain some threads open
Remote the exception for empty arguments.
Fixes #4023

---

• Change in CHANGELOG.md described
• Tests created for changes
• Manually tested changed features in running JabRef
• Screenshots added in PR description (for bigger UI changes)
• Ensured that the git commit message is a good one
• Check documentation status (Issue created for outdated help page at help.jabref.org?)

[abepolk]

Hi,

I'm curious why you eliminated the parser check in the message handler.

Also, I'm looking into how JabRef detects instances already running. Is it true that it checks for a connection to the port specified in preferences?

Thanks!

[Siedlerchr]

The argument parse threw an error when no arguments were passed.

And the second question, yes, JabRef opens a socket and listens for connections to it. Arguments e.g files to open should then be passed to the already running instance.

[abepolk]

I had trouble running two instances of JabRef through Gradle. Should I be running ./gradlew run in two separate bash windows or is that wrong because it tries to compile both times?

[Siedlerchr]

In Eclipse I simply can start two instances.
In terminal you probably need to start a new window
PS: happy new year

[abepolk]

Happy New Year!

In Eclipse I have been getting an error Error: Could not find or load main class org.jabref.JabRefMain, so I had been using gradlew. When I open a second window and run gradlew run, it tries to compile, but it throws an error. It works fine for the first JabRef instance.

[Siedlerchr]

Run gradlew eclipse

[abepolk]

I get:

MacBook-Air-2:jabref Abe$ ./gradlew eclipse

Task :eclipse
UI preferences already exist and will not be overridden. Use task 'cleanEclipse' first.

BUILD SUCCESSFUL in 5s`

Then I run JabRef in Eclipse and get the same error.

[tobiasdiez]

The build process should create a jar which you can run as often as you want using java -jar ... (or you use the jar of an installed version of JabRef in addition to gradlew run).