Use the Refactor
menu. It has an item "encapsulate fields" which generates getters and setters just as "Source -> Generate Getters and Setters" does, but in addition it replaces all usages of the fields and makes the fields private.
(As a mnemonic: To change the structure of existing code (i.e. to refactor it), use the Refactor
menu. To generate new code that is not used yet, use the Source
menu. That is, if you create a new class with some getters and setters, you can use the help of the Source
menu by coding the fields only and auto-generate the getters and setters afterwards. However if you want existing code to use getters and setters instead of direct field access, this is a classic case of code Refactor
ing.)