Introduction to OOP vs. POP

A variable that belongs to the class itself, not to any specific object of the class.

A method that belongs to the class itself, not to any specific object of the class.

In Java, access modifiers determine how other parts of a program can access members (variables, methods, and constructors) of a class.

A method that belongs to the class itself, not to any specific object of the class.

A variable declared with the keyword static that holds a single copy, regardless of how many instances of the class are created.

The public access modifier allows members to be accessed from anywhere within the program.

The protected access modifier allows members to be accessed from within its own class, its subclasses, and within the same package.

The private access modifier allows members to be accessed only from within the same class.

An error that occurs when you try to cast an object to a type that it is not compatible with.

The process of converting an object of one type to another type.

A method in a subclass that has the same name and parameters as a method in its superclass.

A method declared in a subclass that can be accessed only within that subclass.

A method declared in a subclass that can be accessed within the same package or by subclasses in other packages.

A class that inherits properties and methods from another class.

A class that is the source of inheritance for other classes.

An object created from a class, representing an instance of that class.

A static variable belongs to the class itself, not to any specific object. All instances of the class share the same copy of the static variable.

A static method belongs to the class itself, not to any specific object. It can be called directly using the class name.

An instance variable is specific to each object of a class. Each object has its own copy of the instance variable.

An instance method is specific to each object of a class. It can only be called using an object of that class.

You can access a static variable or call a static method using the class name, regardless of whether an object of the class exists.

You can modify a static variable using an object, but the change will be reflected for all instances of the class.

No, you cannot call an instance method directly using the class name. You need an object to call an instance method.

No, you cannot access an instance variable directly using the class name. You need an object to access an instance variable.

The throws keyword in Java method declarations indicates the types of exceptions the method might throw, but it doesn't prevent the program from crashing if an exception occurs.

A try-catch block allows you to handle exceptions in your Java code. You put code that might cause an exception within the try block. If an exception occurs there, the appropriate catch block is executed, which allows you to handle the error gracefully.

In Java, the finally block is used to ensure that a piece of code is always executed, regardless of whether an exception occurred or not. It's often used to clean up resources or close connections, making sure these actions happen even if the program encounters an error.

Catching specific exception types is considered a good practice because it allows you to handle different errors in a more targeted way. You can write tailored code to address specific exceptions and provide more meaningful error messages to the user.

Using logging mechanisms in your code helps in debugging and troubleshooting. It records important events and errors, including exceptions, making it easier to diagnose and fix issues in your Java application.

A constructor is a special method that is automatically called when an object is created. It initializes the object's state.

Constructors are differentiated by the number, types, and order of their parameters. This allows different ways to create objects with varying initial values.

A default constructor is a constructor that takes no arguments. It provides a basic initial state for the object.

Constructor chaining is when one constructor calls another constructor within the same class, usually with a different number of parameters. This allows for a more streamlined initialization process.

The this keyword refers to the current object within a class. In constructor chaining, it's used to call another constructor of the same class.

Encapsulation is a fundamental concept in object-oriented programming that involves bundling data and methods that operate on that data within an object.

Encapsulation hides the internal implementation of an object from the outside world, protecting data and providing controlled access through predefined methods.

Encapsulation allows objects to be reused and maintained independently, promoting code modularity and reducing dependencies.

Static methods can be invoked without creating an instance of the class. This means you can call them directly using the class name.

Static methods can access and modify static variables. This is because both static methods and static variables belong to the class.

Static methods serve as utility or helper functions that don't require object-specific state. They are useful when a function doesn't need to access instance variables.

Static methods can be used for managing a state shared by all instances of a class, like a counter. All instances share the same static variable value.

To call a static method or access a static variable, you use the class name followed by the dot operator and the method name or variable name - e.g., ClassName.staticMethod() or ClassName.staticVariable.

Static variables are declared using the 'static' keyword and belong to the class itself, not to individual objects.

Static variables are created only once, regardless of how many instances of the class are created. All instances share the same copy of the static variable.