Difference between ALL_OBJECTS and DBA_OBJECTS

One needs to understand how the data dictionary is structured. There are USER_* views, ALL_* views, and DBA_* views. USER_* views are views on those things that the current user owns. ALL_* views are views on those things that the current user owns, and has privileges to access. DBA_* views are views on all things in the database. So USER_OBJECTS lists just the objects owned by the current user. ALL_OBJECTS lists all the objects owned by the current user and those objects the current user has access to. DBA_OBJECTS lists every single object in the database.