Confusing message about JAVA_HOME

[mhsmith]

Describe the bug

I got this message on macOS:

*************************************************************************
** WARNING: JAVA_HOME does not point to a Java 17 JDK                  **
*************************************************************************

    Android requires a Java 17 JDK, but the location pointed to by the
    JAVA_HOME environment variable:

    /Library/Java/JavaVirtualMachines/amazon-corretto-8.jdk/Contents/Home

    isn't a Java 17 JDK (it appears to be Java 1.8.0_352).

    Briefcase will use its own JDK instance.

This didn't make any sense, because I didn't have any JAVA_HOME environment variable. It turns out it was actually getting the path by running /usr/libexec/java_home.

Steps to reproduce

• Install a Java version other than 17, and make sure its location is returned by /usr/libexec/java_home
• Remove or rename Briefcase's existing Java 17 installation, if any
• Unset JAVA_HOME
• Run briefcase build android

Expected behavior

The message should correctly indicate where the path came from.

Screenshots

No response

Environment

• Operating System: macOS
• Python version: 3.8
• Software versions:
  • Briefcase: 96479a0

Logs

No response

Additional context

No response