pycharm launching bug when oracle & openjdk installed on the same machine

[NaSH]

like the bug #1617541 I've reported last year,
in pycharm there's the same bug in the file /usr/share/pycharm/bin/pycharm.sh

JDK=`update-alternatives --list java | grep java-8 | sed 's,jre/bin/java,,'`

return 2 lines
/usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java
/usr/lib/jvm/java-8-oracle/jre/bin/java

so it won't affect a value on JDK, and... as a result, won't start pycharm

like we can see here : https://askubuntu.com/questions/748440/pycharm-does-not-start-because-no-jdk-found
the bug exist at least since last year, but wasn't reported correctly :'(