Bug can be defined as the abnormal behavior of the software. No software exists without a bug. The elimination of bugs from the software depends upon the efficiency of testing done on the software. A bug is a specific concern about the quality of the Application under Test (AUT).
Bug Life Cyle
In software development process, the bug has a life cycle. The bug should go through the life cycle to be closed. A specific life cycle ensures that the process is standardized. The bug attains different states in the life cycle.