Where did I set my JAVA_HOME on my Linux?

Hello guys,

I use Linux Mint and need to use my maven with openjdk11, but it seems like it is configured to use jdk8 in some way and I can frankly not figure out how I did it.
Please look at this output:

fredrik@linuxTwo:~$ java -version
openjdk version "11.0.9.1" 2020-11-04
OpenJDK Runtime Environment (build 11.0.9.1+1-Ubuntu-0ubuntu1.18.04)
OpenJDK 64-Bit Server VM (build 11.0.9.1+1-Ubuntu-0ubuntu1.18.04, mixed mode, sharing)

fredrik@linuxTwo:~$ mvn -version
Apache Maven 3.6.0
Maven home: /usr/share/maven
Java version: 1.8.0_181, vendor: Oracle Corporation, runtime: /opt/java/jdk1.8.0_181/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "4.15.0-20-generic", arch: "amd64", family: "unix"

fredrik@linuxTwo:~$ echo $JAVA_HOME
/opt/java/jdk1.8.0_181

fredrik@linuxTwo:~$ cat /etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games"

fredrik@linuxTwo:~$ sudo update-alternatives --config java
[sudo] password for fredrik:
There are 3 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                        Priority  Status
------------------------------------------------------------
  0            /usr/lib/jvm/java-11-openjdk-amd64/bin/java  1111      auto mode
  1            /opt/java/jdk-10.0.2/bin/java                1        manual mode
  2            /opt/java/jdk1.8.0_181/bin/java              1        manual mode
* 3            /usr/lib/jvm/java-11-openjdk-amd64/bin/java  1111      manual mode

Press <enter> to keep the current choice

, or type selection number:

fredrik@linuxTwo:~$

Is there any other place that I might have set my system to use jdk8?

Best regards
Fredrik