Fix --release param check in bootstrap.bat

[mataha]

The following check will always fail silently due to batch echo always taking strings literally - including double quotes:

echo "public class JavacVersionCheck {}" >%CLASSDIR%\JavacVersionCheck.java
"%JAVAC%" --release 8 -d %CLASSDIR% %CLASSDIR%\JavacVersionCheck.java >nul 2>&1

With the following error message:

JavacVersionCheck.java:1: error: class, interface, or enum expected
"public class JavacVersionCheck {}"
^
1 error

Even with that fixed, the next statement will crash and burn on systems that do not have Command Extensions enabled (e.g. invoked with cmd /y):

IF %ERRORLEVEL% EQU 0 SET JAVAC_RELEASE_VERSION="--release 8"

With the following error message:

EQU was unexpected at this time.

In order to accommodate that, those checks have been corrected.

[jaikiran]

Hello @mataha, what you propose here looks OK to me. However, I haven't been able to reproduce the issue that prompted this change. Is there some specific Windows version where this can be reproduced or how did you notice this issue?

[mataha]

Hello @mataha, what you propose here looks OK to me. However, I haven't been able to reproduce the issue that prompted this change. Is there some specific Windows version where this can be reproduced or how did you notice this issue?

Hello,

Try these minimal examples:

cmd /d /y /c "echo "public class JavacVersionCheck {}" >check.java && javac check.java"

cmd /d /y /c "if %ERRORLEVEL% equ 0 echo Success."

As for how I've noticed the issue: I wanted to analyze the bootstrapping code (having come here from Bootstrappable Builds); as I write a lot of Batch scripts as a result of my hobby, the quotes in echo struck me as a red flag immediately.

[mataha]

These, of course, can be run on all Windows versions.

[jaikiran]

Thank you @mataha for those details. I have now merged this PR and added you (Mateusz Kazimierczuk) as a contributor to our contributors list.

[mataha]

The pleasure is mine!