get variable from another class java with code examples

In Java, a class is a blueprint that defines the properties and behavior of an object. Sometimes we need to access the variables and methods of one class from another class. This can be done through object creation and method invocation. In this article, we will discuss how to get a variable from another class in Java with code examples.

Getting a Variable from Another Class

To get a variable from another class in Java, we need to follow these steps:

  1. Create an instance of the class whose variable we want to access.
  2. Use the dot operator (.) to access the desired variable.
  3. Use the getter method to get the value of the variable.

Let's see an example of how to get a variable from another class in Java.

Example:

Suppose we have two classes, Employee and Company. The Company class has a variable named employeeCount, which holds the total number of employees in the company. We want to access this variable from the Employee class.

Here is the code for the Company class:

public class Company {
    private int employeeCount;

    public Company(int employeeCount) {
        this.employeeCount = employeeCount;
    }

    public int getEmployeeCount() {
        return employeeCount;
    }
}

And here is the code for the Employee class:

public class Employee {
    private String name;
    private int age;

    public Employee(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public void printEmployeeCount() {
        Company company = new Company(1000);
        int employeeCount = company.employeeCount;
        System.out.println("Total number of employees in the company: " + employeeCount);
    }
}

In the printEmployeeCount() method, we create an instance of the Company class and access the employeeCount variable using the dot operator. We then print the value of the variable using System.out.println().

However, this approach is not a good practice since we are directly accessing the private member variable of another class. A better way to get the value of a variable from another class is by using getter methods.

Using Getter Method to Access a Variable from Another Class

A getter method is a method that is used to get the value of a private member variable. Let's see how to get a variable from another class using a getter method.

Example:

In this example, we have the same two classes, Employee and Company. The Company class has a private member variable named employeeCount, and a public getter method named getEmployeeCount().

Here is the modified code for the Company class:

public class Company {
    private int employeeCount;

    public Company(int employeeCount) {
        this.employeeCount = employeeCount;
    }

    public int getEmployeeCount() {
        return employeeCount;
    }
}

And here is the Employee class:

public class Employee {
    private String name;
    private int age;

    public Employee(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public void printEmployeeCount() {
        Company company = new Company(1000);
        int employeeCount = company.getEmployeeCount();
        System.out.println("Total number of employees in the company: " + employeeCount);
    }
}

In the printEmployeeCount() method, we create an instance of the Company class and call the getEmployeeCount() method on it to get the employeeCount value. We then print the value of the variable using System.out.println().

Conclusion

Getting a variable from another class in Java can be done by creating an instance of the class whose variable we want to access, using the dot operator to access the variable, and using a getter method to get the value of the variable. Accessing private member variables of a class directly is not a good practice, and getter methods should be used instead.

I can give you more information about the previous topic. Please let me know which topic you want to learn more about.

Popular questions

Sure, here are 5 questions and their answers related to getting a variable from another class in Java.

Q1. What is the dot operator used for in Java?
A: The dot operator (.) is used in Java to access the properties and methods of a class. It is used to access the variables, methods, and constructors of an object.

Q2. How can we access a private variable of another class in Java?
A: Accessing a private variable of another class in Java is not recommended as it can break encapsulation. A better way to access a private variable is by using a getter method provided by the class.

Q3. What is a getter method in Java?
A: A getter method is a public method in a class that is used to get the value of a private variable. It provides a way to access the private variable without directly accessing it, which enhances encapsulation.

Q4. Why should we use a getter method instead of directly accessing a private variable in another class?
A: Using a getter method to access a private variable provides better encapsulation. Directly accessing a private variable can break encapsulation and make the code less maintainable and prone to errors.

Q5. Can we access a private variable of another class without using a getter method in Java?
A: Yes, it is possible to access a private variable of another class without using a getter method by using reflection. However, using reflection can be complicated and unsafe as it can break encapsulation. Hence, it is not recommended to access private variables directly using reflection.

Tag

Inheritance

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