As many of us might agree, context menus are a great way to place functions where users would intuitively expect them to be.  Right-click on a layer (provided your mouse has a right button) and capabilities specific to that layer should pop-up.  Right-click somewhere else, and the options hovering under the mouse change to something else.  This is a proven approach for helping your users do what they want to do more efficiently. Java developers who are using the ArcGIS Engine development kit are not provided the ability to create context menus right out of the box.  

Steven Rozic and Lalitha Darbhamulla from ESRI recently uploaded a Code Gallery sample that we all hope you will find helpful.  It's called "Creating a Context Menu for Layers", although the source code could be applied in other contexts as well. An extra bonus:  the download includes two options to choose from.  One uses the ArcGIS ToolbarMenu and the other uses the JpopupMenu from the Java Swing package.