Could I recommend both Notepad++ and JGRASP as lightweight beginner IDEs? I like them a lot when writing individual java files and I don't feel like waiting for Netbeans to come up. They both have the basics, such as Indentation Guides, but JGRASP is more focused on Java, while Notepad++ is highly configurable (such as add-ons, custom highlighting, and code-completion). Just my two cents to help everyone.