A simple way to save the 4 parameters is a map with each parameter as a key and its value - the value.
The map is saved to a file using randomaccessfile , writeobject.
You cannot change files in dirassets so the application should do the following when starting :
1. check if the file exists in a directory in another place (for example - dirrootexternal or dirinternal).
2.If the file exists - it is not the first activation - read the file (using readobject) and read the parameters from the map.
3.If the file does not exist - first activation - create the directory and copy the file from dirassets, then read the file and the parameters from the map.