jvr-ks / selja

Selja

(Select Java)

Purpose

The purpose of "Selja" is to switch between different Java versions.
It modifies the Windows (System)-PATH and can set the JAVA_HOME environment-variable too.
Windows only (64 bit)

Caution

This tool changes the Windows (System)-PATH environment variable of your Windows.
Please do not use it, if you cannot handle System-PATH environment variable problems!

• Removes System-PATH entries:

• • All entries containing the characters ".?java.?\bin" or ".?java.?\lib\svm\bin"
• • "C:\Program Files (x86)\Common Files\Oracle\Java\javapath"

The System-PATH is logged to the file "_thePathBackup.txt" before.
(The last 10 values with a timestamp).

HINT

Remember: An already running shell (console) must be reopened to reflect the changes of the Windows-path!
or use the included script "resetvars.vbs", which creates the batchfile "resetvars.bat",
calling this batchfile then creates all environment including Windows-path the variables inside the running shell.
TTake a look at the included batch-file "restApiTest.bat".

Download via Updater (preferred method)

Portable, run from any directory, but running from a subdirectory of the windows programm-directories
(C:\Program Files, C:\Program Files (x86) etc.) is not recommended!
Installation-directory (is created by the Updater) must be writable by the app!

To download selja.exe 64 bit Windows from Github please use:

updater.exe 64bit

(Updater viruscheck please look at the Updater repository)

• From time to time there are some false positiv virus detections Virusscan at Virustotal see below.

The default installation-directory is:
C:\jvrde\selja

Open this directory with your filemanger.
"selja.exe" does the work (stays running as a service).
The "javaVersion.exe" shows the actual selected Java version (does nothing more than a "java -version" command).
There are some batch-files to play with:

• testRestApi.bat
• testDirectCall.bat
  (Run them as an admin)
  Selja does not download or install any Java resources!

How it works

This simple tool can switch among different java runtime versions.
Uses a Powershell command to set the System-Path (64 bit Powershell must be available),
must be run as an administrator therefor!

With a [Click] on an entry in the list:

1. All PATH entries containing the following characters:
   "\java\bin"
   (eventually more to come ...)
   are removed!

The Java bin-directory is prepended to the path then.

2. The "JAVA_HOME" environment-variable is set accordingly.

3. If the Configuration-file contains an entry in the section [config]: setEXE4J_JAVA_HOME="yes",
   the environment-variable "EXE4J_JAVA_HOME" is set to the "JAVA_HOME" path too.

If the Selja window loses the focus (or by a click on the window minimize button),
Selja goes to the background and can be activated again via the hotkey (default is: [ALT + j]).
(or the REST-Api)

Other click-operations currently defined:

Click-modifier	Operation
[Shift]	edit selected entry
[Ctrl]	open the path with the default filemanager

Configuration

Configuration is done by a few configuration-files,
use Notepad++ to edit the configuration-files.

Definitions-file:
"selja.txt",
contains on each line delimited by a comma or a tab:

Entry 1	Entry 2	Entry 3	Entry 4
The selection-name,	path of the JDK directory,	path of the JDK bin-directory *)	additional path

selection-name: Blanks are NOT allowed in the selection-name!

Path of the Java-directory:
The path to the JDK
(If you only have a JRE, this tool is not for you).

*) Path of the Java bin-directory: In most cases the \bin subdirectory of the JDK.
Three points "..." is a shortcut of the Path to the Java-directory!

additional path :
Can be used if another subdirectory must be added to the path.

Attention: Remove any trailing "\" from the path!

[Config-file]

The [Config-file] ("selja_COMPUTERNAME.ini") is generated automatically, if it doesn't exist already.
There is a menu-button to edit the [Config-file] via an external plain-text-editor.

Section [hotkeys]:
Hotkeys can be set to "off" by adding the word "off" to the definition.
The two app-hotkeys defaults are:
menuhotkey="!j", i.e. [ALT] + [j] to show the app-window
exithotkey="+!j", i.e. [SHIFT] + [ALT] + [j] to exit the app and remove it from memory
(you may use the button "Kill the app" also)

Primary hotkey modifiers:

Hotkey prefix	Modifier Key	Remark
!	[ALT]
^	[CTRL]
#	[WIN]
+	[SHIFT]

Other Autohotkey Hotkeys hotkeys-characters are usable,
but are untested.
Only simple hotkeys are good to remember and fast to access!

You may use the included extra app "javaVersion.exe" to check the actual java-version. (Just executes a java -version command).

Section [config]:
If the app window is reopened after hiding (autohiding if focus is lost) or at a fresh start of the app,
the size of the window may be incorrect (due to a bug).
The parameters:
windowWidthOffset=VALUE
and
windowHeightOffset=VALUE
may compensate the size error (if app window is not maximized).
They must be set manually once (trial and change method).
Examples:
My laptop J20 has a display resolution of 3840 x 2160 and windows dpi-scaling is set to 350%.
Using: [config] ... windowWidthOffset=3 windowHeightOffset=129 ... everything is fine then. My older laptop J70 has a display resolution of 1280 x 800 and windows dpi-scaling is set to 100%.
Using: [config] ... windowWidthOffset=3 windowHeightOffset=52 ... everything is fine then.

Start

"selja.exe" shows the selja gui-window.
"selja.exe hidewindow" runs selja in the background, use the hotkey to show the gui-window.

If Selja loses the focus, the gui-window is closed and Selja runs in the background, use the hotkey to show the gui-window.
(It is NOT in the tasklist then!)

Hotkeys are configurable by editing the configuration-file "selja.ini".
Use Notepad++ to edit the configuration-file.
Hotkey modifier symbols. Only simple Hotkey modifications are reflected in the menu.
(Parsing is limited to [CTRL], [ALT], [WIN], [SHIFT]).

Requirements

• Windows 10 or later only.

Sourcecode

Github URL github. Autohotkey format

Hotkeys

Overview of all default Hotkeys used by my Autohotkey "tools"

RestApi

If Selja is running it listens to commands of the form:
curl http://localhost:65500/selja?version=(graalvm-ce-java8-21.2.0)
or URL in a browser:
http://localhost:65500/selja?version=(graalvm-ce-java8-21.2.0)

Setting via the server takes a few seconds!

The port-number is defined in the Configuration-file: "seljaRestPort=65500" (65500 is default)

Use "restapioff" start-parameter to disable the RestApi server.

Can set the Scala-version (the Windows-Path) inside a batch-file now, without being an admin,
but a batch-process gets its environment at the start (and inherits it to any subprocess).

Using the Visual Basic script, "resetvars.vbs", which generates a batchfile "resetvars.bat" in the temporary directory,
environment variables can be reread, example batchfile,
(needs curl and installed jdk8-271-Oracle + graalvm-ce-java11-21.2.0):

@rem restApiTest.bat

@echo off
echo Version is:
call java -version
echo.
timeout /t 5

@rem activate "old" version
call curl http://localhost:65500/selja?version=(jdk8-271-Oracle)
echo.
timeout /t 3

@rem reread environment variables
call %~dp0resetvars.vbs
call %TEMP%\resetvars.bat

echo.
echo Version now is:
call java -version
echo.

timeout /t 5

@rem back to actual version
call curl http://localhost:65500/selja?version=(graalvm-ce-java11-21.2.0)
echo.
timeout /t 3

@rem reread environment variables
call %~dp0resetvars.vbs
call %TEMP%\resetvars.bat

echo.
echo Version now is:
call java -version
echo.

pause

("resetvars.vbs" must be in the Windows-Path)

** Besides that, the purpose of "selja" is NOT to temporary switch the Scala-version in a batch-file,
because this can be done with path=scalapathXYZ;%path% and "set SCALA_HOME= ..." etc. !**

Latest changes

Version (>=)	Change
0.129	removes duplicate entries from windows-path, i.e.: "java ... \bin", "jdk ... \bin", "openjdk ... \bin",
0.126	[Config-file] changed to ("selja_COMPUTERNAME.ini") (UTF-16 LE-BOM encoded)
0.125	Updater integration
0.122	Some Gui-bugs fixed
0.118	File "mime.type" created auto. if not existent
0.117	UAC request integrated
0.106	Default port is: 65500

Known issues / bugs

Issue / Bug	Type	fixed in version
Scala 3 (sbt console) fails with "graalvm-community-openjdk-21+35.1"	issue	---
Version-display has the wrong position	issue	0.105

License: GNU GENERAL PUBLIC LICENSE

Take a look at the file "license.txt"

Start of development: 2020/10/15

Copyright (c) 2020 J. v. Roos

Virusscan at Virustotal

Virusscan at Virustotal, selja.exe 64bit-exe, Check here
Use [CTRL] + Click to open in a new window!