When you talk with people about learning to program, and especially learning to program in Java, the BlueJ environment is often mentioned as a good introductory environment to get started. BlueJ is a free Java Development Environment designed for beginners, used by millions worldwide. It is also is an excellent environment in which to gain a good understanding of fundamental principles of object-oriented programming.
Author Micheal Kölling explains "When asked why beginners should not just start by using Eclipse or NetBeans— environments known for their excellent toolset and great functionality—the answer typically points to the great value of BlueJ’s simplicity and interactivity for gaining a thorough understanding of programming principles."
Learn more by reading "Interactive Objects with BlueJ."
Author Michael Kölling is a professor at the School of Computing, University of Kent, in Canterbury, England. His research interests are in the areas of object-oriented systems, software tools, programming languages, computing education, and HCI. He is the author of two Java textbooks and is the lead developer of BlueJ and Greenfoot.