Object in oracle giving as invalid (Invalid)

I gave select * from all_objects where object_name = 'meu_objeto'; . Well, that way, I had 4 lines. Two referring to SYNONYM and this does not interest me and two more lines: PACKAGE and PACKAGE BODY . In the (tuple) line referring to PACKAGE BODY , in the Status column, is INVALID . Must contain errors in code. How do I debug or see these errors in the package body? My object is a Package.