As a beginner in java, you really just need java, javac and a text editor. The problem is less the ecosystem and more just the language isn't a good starting point for a beginning programmer in a formal education setting.
Until you depend on anything, like a unit testing library. Manually managing CLASSPATH isn't fun. I think Java is a fine way to learn OOP (it was my introductory computing language), although I'm now of the opinion that OOP is a big distraction.