Bug in software testing is a defect in a component or system or software that can cause the component or system to fail to perform its required functions.

1. Performance bugs 2. Security Bugs 3. Unit level bugs 4. Functional bugs 5. Usability bugs 6. Syntax errors

Bug Free  System

There is no such thing as bug free software. But we can minimize the volume and the severity of the bugs present, as well their impact.