Maven The JAVA_HOME environment variable is not defined correctly - even though it looks right

Question

I cannot run Maven from terminal on MacOS because it says

The JAVA_HOME environment variable is not defined correctly, this environment variable is needed to run this program.

Every Google hit on the problem says not to have a space in your export command ... I only wish it were that simple ... here is some output

export JAVA_HOME='/Library/Java/JavaVirtualMachines/jdk1.8.0_311.jdk/Contents/Home'
mvn -version

The JAVA_HOME environment variable is not defined correctly,
this environment variable is needed to run this program.

ls $JAVA_HOME

COPYRIGHT               THIRDPARTYLICENSEREADME.txt     jmc.txt                 man
LICENSE                 bin                             jre                     release
README.html             include                         legal                   src.zip
THIRDPARTYLICENSEREADME-JAVAFX.txt                      javafx-src.zip          lib

$JAVA_HOME/bin/java -version

java version "1.8.0_311"
Java(TM) SE Runtime Environment (build 1.8.0_311-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.311-b11, mixed mode)
michael on Mikes-MacBook-Pro (c for commands)

mvn

The JAVA_HOME environment variable is not defined correctly,
this environment variable is needed to run this program.

export JAVA_HOME='/Library/Java/JavaVirtualMachines/jdk-17.0.2.jdk/Contents/Home'
echo $JAVA_HOME

/Library/Java/JavaVirtualMachines/jdk-17.0.2.jdk/Contents/Home

export JAVA_HOME='/Library/Java/JavaVirtualMachines/jdk1.8.0_311.jdk/Contents/Home'
echo $JAVA_HOME

/Library/Java/JavaVirtualMachines/jdk1.8.0_311.jdk/Contents/Home

I even moved my .bash_profile to another folder and started a new session. I also tried a brew uninstall then a brew install ... with no luck.

Any ideas?

Edit:

Inside the mvn command, which is a script, here is where it is apparently failing:

if [ -z "$JAVA_HOME" ] ; then
  JAVACMD="`\\unset -f command; \\command -v java`"
else
  JAVACMD="$JAVA_HOME/bin/java"
fi

if [ ! -x "$JAVACMD" ] ; then
  echo "The JAVA_HOME environment variable is not defined correctly," >&2
  echo "this environment variable is needed to run this program." >&2
  exit 1
fi

I copied this line

JAVACMD="$JAVA_HOME/bin/java"

and used it ... this was my results ... so no idea why it's failing inside the script - but my knowledge of bash script is very limited.

JAVACMD="$JAVA_HOME/bin/java"
$JAVACMD -version

java version "1.8.0_311"
Java(TM) SE Runtime Environment (build 1.8.0_311-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.311-b11, mixed mode)

I even modified the script to this

echo $JAVACMD
if [ ! -x "$JAVACMD" ] ; then
  echo "The JAVA_HOME environment variable is not defined correctly," >&2
  echo "this environment variable is needed to run this program." >&2
  exit 1
fi

And this is my output

mvn

/Library/Java/JavaVirtualMachines/jdk-17.0.1.jdk/Contents/Home/bin/java
The JAVA_HOME environment variable is not defined correctly,
this environment variable is needed to run this program.

Next, I took out the negative test in the if then statement so it would pass and now its saying this:

mvn

/usr/local/Cellar/maven/3.8.5/libexec/bin/mvn: line 194: /Library/Java/JavaVirtualMachines/jdk-17.0.1.jdk/Contents/Home/bin/java: No such file or directory
/usr/local/Cellar/maven/3.8.5/libexec/bin/mvn: line 194: exec: /Library/Java/JavaVirtualMachines/jdk-17.0.1.jdk/Contents/Home/bin/java: cannot execute: No such file or directory

Im going to check folder permissions in that Library folder.

Answer 1

Ultimately, the problem was that the mvn command (which again is a script, not a compiled program) makes a call to $HOME/.mavenrc and inside of that file, was a different path assignment for $JAVA_HOME which was identical to my path, but instead of referencing jdk17.0.2, it was trying to reach jdk17.0.1 and I had uninstalled that jdk long enough prior to having this problem that I had forgotten I removed it.

Nonetheless, one expects a command that one executes to rely on live environment variables that are in place and not to refer to some other file that has a re-definition for an existing environment variable.

I blame Maven for not having their script first check the live environment for the paths it needs before deferring to one that was defined in the past.