Deleting a JRE definition
You can delete Java runtime environment definitions that are available for executing Java programs in the workbench.
Java development tools (JDT)
Working with JREs
Java > Installed JREs preference page.
Select the definition you want to delete and click Remove.
Check the box for the definition that you want to use as the default JRE for the workbench.
Adding a new JRE definition
Choosing a default JRE
Choosing a JRE for launching a project
Installed JREs preference page