Setting the variable does not change anything for the shell. This is normal. To make the “java.exe” work in the shell, you would need to add the folder containing java.exe to your PATH, as well, not just sonarqube’s bin directory. – but that doesn’t matter. Sonarqube now finds java.exe just fine,
The new problem is, that your machine seems to be too low on RAM to run the sonarqube server process.
Do you have any other machine available with more RAM, or maybe it helps if you close some other programs (e.g. webbrowser, eclipse, …) before starting sonarqube.