What are the reasons for restricting access to primitive data that can be modified inside called methods?

Access restriction to primitive data, which can be modified within methods, is related to the principles of encapsulation and data security. If primitive data (e.g., int, boolean) is accessible directly:

• Control over changes is violated, which can lead to unpredictable program behavior.
• Debugging and code maintenance become more complex, as changes can occur from different parts of the program.
• The risk of errors related to incorrect object state increases.

Therefore, fields are usually made private, and access to them is provided through methods (getters and setters), which can control and validate changes. This improves the reliability and maintainability of the code.