B4J Code Snippet Run B4J console app

Depends on jShell. Tested on Windows. Expected to work on Mac and Linux as well.
This code will not work when called from a standalone package. More powerful implementation is available here: https://www.b4x.com/android/forum/threads/jarcaller-run-and-kill-non-ui-jars.168284/

'Jar - Path to the compiled jar file. Should be a non-ui / console app.
'Args - Optional string arguments.
Private Sub RunJar(Jar As String, Args As List)
    Dim shl As Shell
    Dim javaExe As String = File.Combine(GetSystemProperty("java.home", ""), "bin/java")
    Dim NewArgs As List
    NewArgs.Initialize
    NewArgs.Add("-jar")
    NewArgs.Add(Jar)
    If Initialized(Args) Then NewArgs.AddAll(Args)
    shl.Initialize("shl", javaExe, NewArgs)
    shl.WorkingDirectory = File.GetFileParent(Jar)
    shl.Run(-1)
    Wait For shl_ProcessCompleted (Success As Boolean, ExitCode As Int, StdOut As String, StdErr As String)
    Log(StdOut)
    Log(StdErr)
End Sub

Usage example:

RunJar("C:\Users\H\Downloads\projects\ccc\Objects\ccc.jar", Array("aaa", "bbb", "ccc"))

 

[Erel]

If you want to call this method and wait for the process to complete:
1. Change signature to:

Private Sub RunJar(Jar As String, Args As List) As ResumableSub

2. Add to the sub:

Return Success And ExitCode = 0 'depending on the process you are calling...

Usage:

Wait For (RunJar(...)) Complete (Success As Boolean)

 

[aeric]

If you want to call this method and wait for the process to complete:
1. Change signature to:

Private Sub RunJar(Jar As String, Args As List)

2. Add to the sub:

Return Success And ExitCode = 0 'depending on the process you are calling...

Usage:

Wait For (RunJar(...)) Complete (Success As Boolean)

Is it missing As ResumableSub?

 

[cklester]

Is it missing As ResumableSub?

ha! I was wondering what was missing.

 

[Erel]

Is it missing As ResumableSub?

Yes. Fixed.

 

[marcick]

Interesting. I would need this also, Is it difficult to implement?

1. check if the JAR is already running
2. kill the JAR before restart

I spent a morning with ChatGpt with tons of solutions and nothing working ........

 

[Tim Chapman]

I have good luck with Perplexity AI in programming B4J.

 

[Chris2]

Interesting. I would need this also, Is it difficult to implement?

1. check if the JAR is already running
2. kill the JAR before restart

I spent a morning with ChatGpt with tons of solutions and nothing working ........

Killing forgotten Java processes

If you run a non-ui app in release mode and then close the IDE, then the process will continue running. It is difficult to later kill it with Windows task manager as all the Java processes names are java.exe or javaw.exe. You can use jps, a command line tool included in Java JDK, to find the...

www.b4x.com

 

[marcick]

That's good and works perfect. But how to use those commands inside B4J instead of a cmd line?

 

[Chris2]

That's good and works perfect. But how to use those commands inside B4J instead of a cmd line?

You should really start a new question for this in the Questions forum as it's not specifically realated to this thread's code snippet.

 

[Erel]

1. This code will not work when called from a standalone package. More powerful implementation is available here: https://www.b4x.com/android/forum/threads/jarcaller-run-and-kill-non-ui-jars.168284/

2. It includes a "kill process" feature.