javaw vs java command

[SirStone]

I noticed that from version 0.34.0 the sample bot scripts are configured to use javaw or java depending if the compilation is on windows or not.

While this is not an error I think that is not a good idea as people like me, downloading the already compiled bots, need to manually modify the running bash script to not use jawaw as this command does not exists on linux.

• Is there a reason why this 'javaw' is now required?
• Can't this be scripted directly inside the bash?

[flemming-n-larsen]

I changed to javaw to fix an old and annoying issue on Windows. But I see it causes issues for Linux and macOS.
So I will make a fix for Linux and macOS, so it will use java.exe only on Linux/macOS. 😊

The difference (on Windows) is that javaw (Java Wrapper), which does not open a command prompt window, which is useful for GUI applications where console output is unnecessary:
https://codemia.io/knowledge-hub/path/what_is_the_difference_between_java_javaw_and_javaws

I had an issue where I had to add >nul when calling java on Windows, but I got it solved.

⚙️ The Key Difference

• java.exe

  • Console-based launcher.
  • When you run it, it expects a console window to exist and attaches standard input/output/error streams to it.
  • If you start java.exe from a process that doesn’t have a console (for example, from a GUI program or a service), the absence of a valid console can cause the JVM to misbehave or terminate unexpectedly.
  • Redirecting output with >nul works because it gives java.exe a valid output stream to bind to, avoiding the crash.

• javaw.exe

  • GUI-based launcher.
  • Designed specifically for Windows applications that don’t need a console.
  • It does not attempt to attach to a console window at all, so it runs fine in contexts where no console exists.

So in the case for Windows, we don’t need >nul — it simply ignores console I/O.

[flemming-n-larsen]

@SirStone
I updated the sample bots in the 0.34.1 release, so all the .sh files use java instead of javaw