This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
A JComboBox is unEditable by default. You can make it editable with the setEditable(boolean) command. If you are talking about enabled or disabled you can set that by the setEnabled(boolean) method. Setting a JComboBox enabled(false) will not allow the drop down to be activated. Editing means you can type in your own text into the text field of the Combo Box.