After using the code of Sunjammer i was getting an error (screenshot).
It means, that there was an error while overwriting a file (?).
What means "jre_setup_exe_filename.exe"
Ok, kichik, now i have a look at your link
With NSIS i can check if Flash-player is installed, right?
Can i also check if a JRE/JDK is installed?
If not, could i use a checkbox at the end of the installation?
Many installers are using checkboxes for "view the readme now" and so on, can i use a checkbox for installing the JRE?
So, if the user checks the box "install the JRE now", the installtion of the JRE starts. (In modern UI)