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.

Use of primitives instead of small objects for simple tasks (such as currency, ranges, special strings for phone numbers, etc.)Use of constants for coding information (such as a constant USER_ADMIN_ROLE = 1 for referring to users with administrator rights.)Use of string constants as field names for use in data arrays.