Private
Definition
In the context of programming, private refers to a visibility modifier that restricts access to certain variables or methods within a class. It means that only other members of the same class can access those private elements.
Analogy
Think of a private party where only invited guests are allowed inside. Similarly, in programming, private elements are like exclusive areas that can only be accessed by members of the same class.
Related terms
Public: Refers to a visibility modifier that allows unrestricted access to variables or methods from any part of the program.
Encapsulation: The concept of bundling data and methods together within a class and controlling their access using visibility modifiers like private.
Access Modifier: A keyword used in programming languages to define the accessibility level of classes, variables, or methods.
"Private" appears in:
Study guides (4)
Additional resources (1)
Practice Questions (12)
- Consider the following class definition. public class Animal { private String species; private int age; private double weight; public Animal(String animalSpecies, int animalAge, double animalWeight) { species = animalSpecies; age = animalAge; weight = animalWeight; } public void eat() { weight += 5; } public double getWeight() { return weight; } } Assume that the following code segment appears in a class other than Animal. java Copy code Animal dog = new Animal("Dog", 3, 15); dog.eat(); System.out.println(dog.getWeight()); What is printed as a result of executing the code segment?
- Consider the following class definition: public class Student { private String name; private int age; private String major; public Student(String studentName, int studentAge, String studentMajor) { name = studentName; age = studentAge; major = studentMajor; } public String getName() { return name; } public int getAge() { return age; } public String getMajor() { return major; } } Assume that the following code segment appears in a class other than Student: Student student = new Student("Alice", 19, "Computer Science"); String name = student.getName(); int age = student.getAge(); String major = student.getMajor(); System.out.println(name + " is " + age + " years old and majoring in " + major + "."); What is printed as a result of executing the code segment?
- Consider the following superclass and subclass declarations: ```java public class Shape { private String color; public Shape(String color) { this.color = color; } public String getColor() { return color; } } public class Circle extends Shape { private double radius; public Circle(String color, double radius) { // Circle constructor implementation goes here } } ```
- Why does the following code not compile? public class Student { private int gpa; public getGPA() { return gpa; } // Constructor not shown }
- How can we fix the following class so it compiles? public class Weather { private int currentTemp; public Weather(int temp) { currentTemp = temp; } public void resetTemp() { currentTemp = newTemp; } }
- Why does the following class does not compile? public class Weather { private int currentTemp; public Weather(int temp) { currentTemp = temp; } public void resetTemp(double newTemp) { currentTemp = newTemp; } }
- Which of the following lines of code properly declare a private static variable called "name"?
- Why does the following example class not compile? class ClassName { private String variableName; public static void methodName() { variableName = "exampleString"; } // Constructor not shown }
- What output do we get if we run the following code? class X { private int a; private int y; public X() { this.a = 5; } public X(int y) { this(); this.y = y; System.out.print(a); System.out.print(this.y); } } public class Z { public static void main(String[] args) { X x = new X(3); } }
- Does the following code compile successfully? ```java class X { private int a; private int y; public X() { this.a = 10; } public X(int y) { this(); this.y = y * 10; System.out.print(this.a + " "); System.out.print(this.y + " "); } } public class Z { public static void main(String[] args) { X x = new X(5); } } ```
- What is the output of the following code? ```java class X { private int a; private int y; public X() { a = 15; } public X(int y) { this(); X.y = y; System.out.print(this.a + " "); System.out.print(this.y + " "); } } public class Z { public static void main(String[] args) { X x = new X(5); } } ```
- What output do we get if we run the following code? ```java class X { private int a; private int y; public X() { this.a = 3; } public X(int y) { this("z"); this.y = y; System.out.print(this.a + " "); System.out.print(this.y + " "); } } public class Z { public static void main(String[] args) { X x = new X(7); } } ```
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