Introduction Checked exceptions in Java are exceptions that are checked at compile-time. These exceptions must be either caught using a try-catch block or declared in the method signature using the throws keyword. Checked exceptions are typically used for conditions from which recovery is possible, such as file I/O errors or network issues. Table of Contents …
In this chapter, you will learn how to define custom exceptions (user-defined exceptions) in Java with examples. Table of Contents What are Custom Exceptions? Benefits of Using Custom Exceptions Creating Custom Exceptions Throwing Custom Exceptions Catching Custom Exceptions Example: Custom Checked Exception Example: Custom Unchecked Exception Best Practices for Custom Exceptions Real-World Analogy Conclusion 1. …
Introduction The throw and throws keywords in Java are used to handle exceptions. They play a crucial role in defining how exceptions are propagated and handled in Java programs. Understanding these keywords is essential for writing robust and fault-tolerant code. Table of Contents What is the throw Keyword? What is the throws Keyword? Difference Between …
Introduction The finally block in Java is a mechanism to execute a block of code regardless of whether an exception is thrown or not. It is typically used for cleanup activities, such as releasing resources like file streams, database connections, and other system resources. The finally block ensures that important code is always executed, even …
Introduction The try-catch block in Java is a mechanism to handle exceptions, ensuring that the program can manage unexpected errors gracefully and maintain its normal flow. It allows you to write a block of code that might throw an exception and define how the program should respond if an exception occurs. Table of Contents What …
Introduction Exception handling in Java is a powerful mechanism that allows developers to handle runtime errors, ensuring that the normal flow of the application is maintained. Exceptions are events that occur during the execution of a program that disrupt its normal flow. By using exception handling, you can make your programs more robust and fault-tolerant. …
Introduction Enums in Java provide a way to define a set of named constants. They are used to represent a fixed set of values and are often used to define categories, states, or modes. Enums are type-safe and provide many features that enhance code readability and maintainability. Table of Contents What are Enums? Benefits of …
Introduction Java packages are a way to organize classes and interfaces into namespaces, providing a structured way to manage large codebases. Packages help in avoiding name conflicts, controlling access, and making the code more modular and maintainable. Table of Contents What are Packages? Benefits of Using Packages Creating and Using Packages Importing Packages Built-in Packages …
Introduction Java wrapper classes provide a way to use primitive data types (int, boolean, etc.) as objects. Each of the eight primitive types has a corresponding wrapper class in Java. These classes are part of the java.lang package and provide methods to manipulate primitive data types and convert them to objects. 1. What are Wrapper …
Introduction Nested classes are classes defined within another class. Java supports several types of nested classes, each serving different purposes and offering various levels of access and functionality. The types of nested classes include Static Nested Classes, Inner Classes, Local Inner Classes, and Anonymous Inner Classes. Table of Contents What are Nested Classes? Types of …
Introduction The super keyword in Java is used to refer to the immediate superclass of the current object. It is a reference variable that is used to access superclass methods, constructors, and fields. The super keyword plays a vital role in inheritance by allowing subclasses to call superclass methods and constructors and to access superclass …
Introduction The this keyword in Java is a reference variable that refers to the current object. It is used to differentiate between instance variables and local variables, invoke current class methods and constructors, and pass the current object as a parameter. Table of Contents What is the this Keyword? Uses of the this Keyword Differentiating …
Introduction Annotations in Java are a form of metadata that provide information about the program but do not have any direct effect on the code execution. They are used to give additional information to the compiler, code analyzers, and frameworks. Annotations can be applied to declarations of classes, fields, methods, parameters, and more. Table of …
Introduction In Java, both interfaces and abstract classes are used to achieve abstraction. However, they have different purposes and use cases. Understanding the differences between them is crucial for designing robust and flexible Java applications. Table of Contents Definition Purpose Key Differences When to Use Interface vs. Abstract Class Real-World Analogy Conclusion 1. Definition Interface …
Introduction An interface in Java is a reference type that contains only abstract methods and static constants. Interfaces provide a way to achieve full abstraction and multiple inheritance in Java. They define a contract that classes must follow, ensuring a certain level of consistency across different classes. Table of Contents What is an Interface? Benefits …
Introduction An abstract class in Java is a class that cannot be instantiated on its own and is meant to be subclassed. It can have both abstract methods (methods without a body) and concrete methods (methods with a body). Abstract classes are used to provide a common definition of a base class that multiple derived …
Introduction Abstraction is one of the four fundamental principles of Object-Oriented Programming (OOP) in Java. It involves hiding the complex implementation details and showing only the necessary features of an object. Abstraction helps to reduce programming complexity and effort by allowing the programmer to focus on what an object does rather than how it does …
Introduction Method overriding is a fundamental concept in Java that allows a subclass to provide a specific implementation for a method that is already defined in its superclass. This feature is a key aspect of runtime polymorphism and helps in designing flexible and extensible code. Table of Contents What is Method Overriding? Benefits of Method …
Introduction Method overloading is a feature in Java that allows a class to have more than one method with the same name, provided their parameter lists are different. Method overloading is a form of compile-time polymorphism that helps to improve code readability and usability. Table of Contents What is Method Overloading? Benefits of Method Overloading …
Introduction Polymorphism is one of the four fundamental principles of Object-Oriented Programming (OOP) in Java. The term "polymorphism" means "many forms," and it allows objects to be treated as instances of their parent class rather than their actual class. Polymorphism enables one interface to be used for a general class of actions, with the specific …
Introduction Hierarchical inheritance is a type of inheritance in Java where multiple subclasses inherit from a single superclass. This type of inheritance is useful when you want to share common functionality among different classes while allowing each subclass to have its own specific features. Table of Contents What is Hierarchical Inheritance? Benefits of Hierarchical Inheritance …
Introduction Multilevel inheritance in Java is a type of inheritance where a class is derived from another class, which in turn is derived from another class. This creates a chain of inheritance. Multilevel inheritance helps to model a more hierarchical structure and promotes code reusability by allowing subclasses to inherit features from multiple levels of …
Introduction Single inheritance is a fundamental concept in Java’s Object-Oriented Programming (OOP). It allows a class (subclass or derived class) to inherit fields and methods from another class (superclass or base class). This enables code reusability and helps to create a hierarchical classification. Table of Contents What is Single Inheritance? Benefits of Single Inheritance Implementing …
Introduction Inheritance is one of the four fundamental principles of Object-Oriented Programming (OOP) in Java. It allows a new class (subclass or derived class) to inherit properties and behaviors (fields and methods) from an existing class (superclass or base class). Inheritance promotes code reusability and establishes a natural hierarchical relationship between classes. Table of Contents …
Introduction Encapsulation is one of the four fundamental principles of Object-Oriented Programming (OOP) in Java. It is the process of wrapping data (fields) and methods (functions) that operate on the data into a single unit, typically a class. Encapsulation helps to protect the data from unintended interference and misuse by restricting access to certain components …