You try to start Cassandra but you get this error:
"[0.000s][warning][gc] -Xloggc is deprecated. Will use -Xlog:gc:./bin/../logs/gc.log instead.
intx ThreadPriorityPolicy=42 is outside the allowed range [ 0 ... 1 ]
Improperly specified VM option 'ThreadPriorityPolicy=42'
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit."
Possible solution #1
Migrate to Linux SUSE or a Red Hat family version of Linux (e.g., CentOS, RHEL or Fedora). We have only seen this problem with Ubuntu Linux.
Possible solution #2
Remove Java version 9 and install Java version 8. To do this (assuming that they were installed via apt-get commands), run these commands:
sudo apt-get -y remove openjdk-9-jre-headless
sudo apt-get -y update
sudo apt -y install openjdk-8-jre-headless gcj-4.8-jre-headless default-jdk