What is the fine-grained topic of the following text: Note: If you have more than one Java Run-time Environment (JRE) installed on your computer, and one or more of the custom toolkit class locations you specified were Eclipse projects, make sure that the custom toolkit projects and the new Java Add-in Extensibility project are using the same JRE. Only return the topic.
Java Run-time Environment (JRE) Configuration for Custom Toolkit Class Locations and Java Add-in Extensibility Project