Example analysis of access permission modifiers for Java functions

There are four access permission modifiers in Java: public (access from anywhere), protected (access to the same package, sub-package and sub-class), package access (access to the same package) and private (access only to the class), Can control the visibility of classes, interfaces, and methods.

Example analysis of access modifiers for Java functions

Access modifiers specify the visibility of classes, interfaces and methods sexual level. In Java, there are the following four access modifiers:

• public: Methods can be accessed from anywhere.
• protected: Methods can only be accessed in the same package or sub-package, and in other classes with subclass relationships.
• Package access (default): Methods can only be accessed in the same package.
• private: A method can only be accessed within the class that contains it.

Practical case:

Suppose we have a Bank class, which has a getAccountBalance method for Get account balance. We want this method to be accessible only through the Bank class outside the Account class.

public class Bank {

    private Account account;

    public Account getAccount() {
        return account;
    }

    public double getAccountBalance() {
        return account.getBalance();
    }
}

class Account {

    private double balance;

    public double getBalance() {
        return balance;
    }
}

In the above example, the getAccountBalance method is declared as public, which means it can be accessed outside the Bank class. However, the getBalance method is declared as private, which means it can only be accessed within the Account class. Therefore, external classes cannot directly access the balance information of the Account class.

Usage Notes:

• Access modifiers are critical to maintaining the security and modularity of your code.
• Carefully choose appropriate access modifiers to ensure that only authorized code can access sensitive data or methods.
• When designing classes and interfaces, you should carefully consider how access modifiers affect the reusability and maintainability of your class.

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