You should use IDE now...
To develop GUI, one had better use IDE. IDE is nothing but a wrapped JDK. To use IDE, you still need set CLASSPATH, add new library, set output path, ..... If you can do all these using JDK, you should be OK with IDE.
As a new Java learner, when should I start using WYSIWYG tools for Java? (WYSIWYG--What You See Is What You Get)