# Overriding the default system libraries for a JRE definition

You can override the system libraries and the corresponding source attachments when adding a JRE.

1. Begin adding a new JRE definition.
2. In the Create JRE dialog, clear the Use default system libraries checkbox.
   If the system was able to determine the set of system libraries, these libraries will already be displayed.
3. Order and/or remove the system libraries that were determined. Add external JARs to the list of system libraries.
4. Associate source with the system libraries using the Attach source button.
5. When you are finished with this dialog, click OK to create the new JRE definition. The new JRE definition will use the customized system libraries (and attached source).

Java development tools (JDT)

Working with JREs
Adding a new JRE definition
Editing a JRE definition

Installed JREs preference page