BlueJ is an integrated Java environment specifically designed for introductory teaching.
Features:
fully integrated environment
graphical class structure display
graphical and textual editing
built-in editor, compiler, virtual machine, debugger, etc.
easy-to-use interface, ideal for beginners
interactive object creation
interactive object calls
interactive testing
incremental application development
Platform:Cross platform ; License:GNU General Public License V2
Reference:https://www.bluej.org/about/what.html