My.openhab is offline

So,I have installed openhab on my rpi2 with raspbian jessie and oracle jdk 8. I have been trying to setup my.openhab but it keeps showing offline. I have double checked the uuid add secret. Set security to off and netmask to I dont understand netmask my router ip is and raspi ip i have also set persistence as given below:
Strategies {
default = everyChange
Items {

  • : strategy = everyChange
    but i cant get openhab to connect

Your netmask is wrong, you should use
Check your java version with
java -version at the console,
you should be at least at version 101 (java is not updated through apt-get update/upgrade!!).
For more hints take a look here:

I tried what u said. I changed net mask to and my java version is 1.8.0_65 but it still doesn’t work

This is not the latest version. It has to be (at least) 1.8.0_101! _65 is known not to work!

ok so updating the java worked