How to use private in java

Private modifier is used in Java to restrict the visibility of members (fields, methods and inner classes) so that they are only visible within the class in which they are defined. It is used for information hiding, encapsulation and data integrity. Private members are only accessible within the class in which they are declared; subclasses and classes in other packages cannot access them. Exceptions are access via getter/setter methods or the reflection API.

Usage of private in Java

In the Java programming language, private is An access modifier that limits the visibility of members (fields, methods, and inner classes) in a class or interface so that they are only visible within the class in which they are defined.

Uses:

private Modifiers are mainly used for the following purposes:

• Information hiding: Hide the internal implementation details in the class to prevent external access, thereby improving the maintainability and security of the code.
• Encapsulation: Ensure that the state and behavior of the class interact with the outside world are controlled by the class itself.
• Data integrity: Prevent external code from modifying or destroying private data and ensure data consistency and integrity.

Syntax:

When using the private keyword to declare class members, the syntax is as follows:

private <成员类型> <成员名称>;

For example:

private int age;
private String name;

Visibility rules:

• Private members can only be accessed within the class in which they are declared.
• Subclasses cannot access private members of the parent class.
• Classes in other packages cannot access any private members.

Exception:

In some cases, private members can also be accessed in other classes, for example:

• Accessed through the getter or setter method.
• Accessed through reflection API.

When to use:

Generally, when the following conditions are met, you should use private Modifier:

• Members are part of the internal implementation of the class and do not need to be exposed to external code.
• Members contain sensitive data and need to be protected.
• The visibility of members needs to be strictly controlled to ensure the correctness and security of the code.

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