Bloaters.

Sometimes different parts of the code contain identical groups of variables (such as parameters for connecting to a database). These clumps should be turned into their own classes.

A class contains many fields/methods/lines of code.

A method contains too many lines of code. Generally, any method longer than ten lines should make you start asking questions.

More than three or four parameters for a method.

Primitives are used instead of small objects for simple tasks (such as currency, ranges or special strings for phone numbers), constants are used to code information (such as USER_ADMIN_ROLE = 1 for users with administrator rights), and string constants serve as field names in data arrays.