Private fields prevent external modification and help maintain control.
Using private fields ensures that the internal state of an object cannot be changed directly from outside the class, preserving the integrity of the object's data. For example, in an e-commerce application, if a Product class has a price field, making it private ensures that only methods within the Product class can change its value, like through a setPrice method that includes validation logic.
Additional Notes
Why is using private fields in Java classes important?