Types of Defects in Software Development

Defects are defined as the deviation of the actual and expected result of system or software application. Defects can also be defined as any deviation or irregularity from the specifications mentioned in the product functional specification document. Defects are caused by the developer in development phase of software. When a developer or programmer during the development phase makes some mistake then that turns into bugs that are called defects. It is basically caused by the developers' mistakes. Defect in a software product represents the inability and inefficiency of the software to meet the specified requirements and criteria and subsequently prevent the software application to perform the expected and desired working. 

Types of Defects: Following are some of the basic types of defects in the software development:

1. Arithmetic Defects: It include the defects made by the developer in some arithmetic expression or mistake in finding solution of such arithmetic expression. This type of defects are basically made by the programmer due to access work or less knowledge. Code congestion may also lead to the arithmetic defects as programmer is unable to properly watch the written code.
2. Logical Defects: Logical defects are mistakes done regarding the implementation of the code. When the programmer doesn't understand the problem clearly or thinks in a wrong way then such types of defects happen. Also while implementing the code if the programmer doesn't take care of the corner cases then logical defects happen. It is basically related to the core of the software.
3. Syntax Defects: Syntax defects means mistake in the writing style of the code. It also focuses on the small mistake made by developer while writing the code. Often the developers do the syntax defects as there might be some small symbols escaped. For example, while writing a code in C++ there is possibility that a semicolon(;) is escaped.
4. Multithreading Defects: Multithreading means running or executing the multiple tasks at the same time. Hence in multithreading process there is possibility of the complex debugging. In multithreading processes sometimes there is condition of the deadlock and the starvation is created that may lead to system's failure.
5. Interface Defects: Interface defects means the defects in the interaction of the software and the users. The system may suffer different kinds of the interface testing in the forms of the complicated interface, unclear interface or the platform based interface.
6. Performance Defects: Performance defects are the defects when the system or the software application is unable to meet the desired and the expected results. When the system or the software application doesn't fulfill the users's requirements then that is the performance defects. It also includes the response of the system with the varying load on the system.
7.  software error: A software error occurs during the development of the software. This error can be in the form of a grammatical error, a logical error where the outcome of a sequence of executions will not result in what was intended or a misinterpretation of the user requirements in the actual written code. It may be in the form of user documentation not matching the software applications operation. An error may or may not be
   detected during the coding or testing of the program before it is released to a customer. 
8. Software Fault: A software fault occurs as a result of an error that remains in the executing program. Not all faults however are detected and the software may continue executing without any obvious problems. There are cases where software faults go undetected for many years of a programs existence.
9. Software Failure: A software failure is a fault that results in a detectable problem; hence it is referred to as a failure. A failure would cause the application to malfunction in an obvious manner that warrants the attention of system maintenance.
10. Boundary and Range Defects: These defects relate to issues where the software does not handle inputs or data outside of specified boundaries or ranges correctly. For example, not handling edge cases or boundary values appropriately.
11. Data Validation Defects: It involves failing to validate user inputs, leading to potential security vulnerabilities or incorrect data handling.
12. Deployment Defects: It includes setup mistakes, installation issues and problems that stop the software from functioning properly in a real-world setting.
13. Integration Defects: When different software modules or components do not function well together, integration errors result. Problems with data synchronization, communication, and functionality may result from this.
14. Documentation Defects: These refer to errors or issues in the accompanying documentation, including user manuals, help files or API documentation. Incomplete or inaccurate documentation can lead to user confusion.
15. Data Defects: These can result in data corruption or loss, inconsistent data storage or issues with data retrieval. For example, data validation errors could lead to incorrect data being stored.

Refer for - differences between defect, bug and failure