I have used and like them both... here's my take on what to use in your case.

1. Use whatever software your instructor is using when learning a language. It makes it simpler to start. Then change to whatever you like.
2. Use an IDE (Integrated Development Enviroment). For Java I'd pick InteliJ (because I have found the Jetbrains IDEs great) or Visual Studio as a second pick (because it's free for individual coders).
3. Pick your text editor: the Atom vs Notepad++, vs others question Both Atom and Notepad++ offer many features and add-ons, making it a long-disputed competition. This is what drives to chose between one and the other, and I have been alternating: On Atom: The good:

• Good looking coding environment
• Good autocomplete
• Project focused structure to your files The bad:
• Higher system resources usage
• Slower loading time (if you are opening and closing)

Notepad++ The good:

• Very light system resources use
• Fast and simple, with decent code higlighting
• Loads very fast The bad:
• Not as pretty as Atom
• Autocomplete and syntax checking is not that good
• File-focused editing