HI
I got exately the same problem: I just installed java, never had it before, and start.sh throws error that there would be no java:
magnus@blablubbb:/opt/openhab$ sudo ./start.sh
Launching the openHAB runtime…
./start.sh: 16: ./start.sh: java: not found
magnus@blablubbb:/opt/openhab$ java -version
java version "1.8.0_91"
Java™ SE Runtime Environment (build 1.8.0_91-b14)
Java HotSpot™ 64-Bit Server VM (build 25.91-b14, mixed mode)
I do not understand what/where/how to debug.
I just tried to run the designer with a similar result, but this time the error message is making more sense:
A Java Runtime Environment (JRE) or Java Development Kit (JDK)
must be available in order to run OpenHAB-Designer. No Java virtual machine
was found after searching the following locations:
/opt/openhab-designer/jre/bin/java
java in your current PATH
So somehow it searches java in a subdirectory of the designer, which does not exists. On the other hand I went to the java webpage and their webpage confirms that I have the latest version sucessfully installed…
I found a solution:
sudo apt-get install default-jre
Another solution may be to really create this directory and placing there a link to the bin folder of java.