I am learning Java and have written a few small useful programs. I am new to spring but have managed to understand the concept of dependency injection for decoupling. I'm trying to applying that in my development work in an enterprise setting. What are the 3 most important design patterns I should master (not for interview purposes but ones that I will use every day in as a good java developer)? Also what are some good java design considerations and practices in coding specifically in Java? My goal is write good decoupled and coherent programs that are easy to maintain that don't make me standout as a java rookie. Stuff like not beginning my package names with com. have already made me precariously visible in my team. But they know I have 2 years of coding experience and its not in java.