https://trends.google.com/trends/explore?date=today%205-y&q=...
Unfortunate, because it had (has?) a great Swing and UML editor, built-in for free.
Maybe I'm wrong and it's awesome now, but I haven't used it for a while in favor of Eclipse, and now, IntelliJ. This graph illustrates the IDE popularity between Intellij and Netbeans. IntelliJ became preferred over Netbeans about mid 2014.
https://trends.google.com/trends/explore?date=all&geo=US&q=i...