I want to write Java programs for the Raspberry Pi Zero (it has 512 MB RAM) and i don't know if i should choose the Java SE (Standard Edition) or the Java ME (Micro Edition). Thanks for help
As long as you can spare the raspberry's resources I'd go with JavaSE. It is wider used and thus enjoys better support and tools.
In case you want to save resources check out JavaME as that is the main reason this thing exists.
What flavor does your OS install when you choose the java package?