JAVA_HOME on Windows

David Madden

Hi,

Why does SQLcl on Windows not use JAVA_HOME as the version of Java to use if it's set? I assumed it did this or used the PATH initially to identify the location of java.exe to use.

Looking at the debug output when running SQLcl I can see it checks the following:

Paths:

..\..\jdk\jre\bin\java.exe

Registry keys:

64-bit search: SOFTWARE\JavaSoft\Java Runtime Environment...

32-bit search: SOFTWARE\JavaSoft\Java Runtime Environment...

64-bit search: SOFTWARE\JavaSoft\Java Development Kit...

32-bit search: SOFTWARE\JavaSoft\Java Development Kit...

64-bit search: SOFTWARE\JavaSoft\JRE...

32-bit search: SOFTWARE\JavaSoft\JRE...

64-bit search: SOFTWARE\JavaSoft\JDK...

32-bit search: SOFTWARE\JavaSoft\JDK...

64-bit search: SOFTWARE\IBM\Java Runtime Environment...

32-bit search: SOFTWARE\IBM\Java Runtime Environment...

64-bit search: SOFTWARE\IBM\Java Development Kit...

32-bit search: SOFTWARE\IBM\Java Development Kit...

64-bit search: SOFTWARE\IBM\Java2 Runtime Environment...

32-bit search: SOFTWARE\IBM\Java2 Runtime Environment...

64-bit search: SOFTWARE\IBM\Java Development Kit...

32-bit search: SOFTWARE\IBM\Java Development Kit...

But never JAVA_HOME or PATH, why?

Incidentally this caused me quite a bit of head scratching to work out why my installation was not working.

David.

Glen Conway

That second link I posted above talks about how the SQL Developer team uses Launch4j - Cross-platform Java executable wrapper to build it's exe files.  I assume the way they configure it, if no JRE is found at ..\..\jdk\jre relative to the location of sql.exe, then Launch4J searches for the highest Java JRE installed on your machine.

That behavior can definitely make life tougher, leading you to add a JRE inside the SQLcl install at ..\..\jdk\jre relative to the location of sql.exe as a last resort.  Otherwise, I suppose you could try to create your own sql.bat file to behave like the bash script for Linux, but few will want to bother with that.

Edit: If you do, start with this 18.1 version hack in and make any necessary changes for it to work with SQLcl 20.2.

Glen Conway

Take a minute to read through a couple of prior discussions:

Re: Java limitation:lower versions of SQLCL available?   -- This describes some general rules for how SQLcl finds the JRE under Windows and Linux.

and

Re: unable to launch SQLCL 18.1  -- This notes especially how one of the rules changed between 17.4 and 18.1, making sql.exe consistent with sqldeveloper.exe

Hope this helps!

David Madden

Thanks @Glen Conway. One of those posts actually help me resolve the issue I was having originally. What I am interested in specifically here though is why the Windows exe does not use JAVA_HOME.

Is it just the assumption that on Windows, people don't use environment variables the same as on Linux?

Glen Conway

That second link I posted above talks about how the SQL Developer team uses Launch4j - Cross-platform Java executable wrapper to build it's exe files.  I assume the way they configure it, if no JRE is found at ..\..\jdk\jre relative to the location of sql.exe, then Launch4J searches for the highest Java JRE installed on your machine.

That behavior can definitely make life tougher, leading you to add a JRE inside the SQLcl install at ..\..\jdk\jre relative to the location of sql.exe as a last resort.  Otherwise, I suppose you could try to create your own sql.bat file to behave like the bash script for Linux, but few will want to bother with that.

Edit: If you do, start with this 18.1 version hack in and make any necessary changes for it to work with SQLcl 20.2.

BG4GRAPH

https://community.oracle.com/tech/developers/discussion/comment/15669130#Comment_15669130

Which permission is required for https://community.oracle.com/message/14456937#14456937? I Can't read it.

Glen Conway

I guess not all links got migrated properly when moving the Oracle Community from the Jive platform to the Vanilla open source platform. I used the Search feature to get the following. I had to quote them to avoid some substitution. I hope they work for you.

"https://community.oracle.com/tech/developers/discussion/comment/14835441#Comment_14835441"

"https://community.oracle.com/tech/developers/discussion/comment/14792180#Comment_14792180"

BG4GRAPH

Indeed they do, thanks!