Core Basics Blog

Throws in Java is a keyword used to declare an exception. It gives an indication to the programmer that the exception may occur during the execution of the program. It is used to declare the exceptions that are not caught by the method but are propagated to the caller method. Why Use Throws in Java? There are several reasons why you would want to use throws in Java: To declare an exception that is not caught by the method but is propagated to the caller method. To provide information to the caller method about the exceptions that may occur during the execution of the method. To avoid the overhead of catching and handling exceptions that are not expected to occur. How to Use Throws in Java Here is an example of how to use throws in Java: public class ThrowsExample { public static void main(String[] args) { try { divide(10, 0); } catch (ArithmeticException e) { System.out.println("Caught an exception: " + e.getMessage()); } ...

Transient is a keyword in Java that is used to prevent serialization of a variable. When a class implements the Serializable interface, all its objects can be serialized, meaning they can be converted into a byte stream and saved to a file or sent over a network. However, there may be certain variables in the class that we do not want to serialize, such as passwords or sensitive data. This is where the transient keyword comes in. What is Transient? Transient is a non-access modifier keyword in Java that is used to prevent serialization of a variable. When a variable is declared as transient, it is not serialized, even if the class implements the Serializable interface. Example of Transient public class Employee implements Serializable { private String name; private transient String password; public Employee(String name, String password) { this.name = name; this.password = password; } public String getName() { return name; ...

Void is a keyword in Java that is used to declare methods that do not return any value. In other words, a method declared with the void keyword does not return any data type, not even null. When a method is declared with void, it means that the method does not return any value to the calling method. Declaring Void Methods A void method is declared using the void keyword followed by the method name and parameters in parentheses. Here is an example of a void method: public void printHello() { System.out.println("Hello, World!"); } In this example, the printHello() method is declared with the void keyword, which means it does not return any value. The method simply prints "Hello, World!" to the console. Using Void Methods Void methods can be used to perform actions that do not require a return value. For example, you can use a void method to print a message to the console, update a database, or perform any other action that does not require a ret...

In Java, the volatile keyword is used to indicate that a variable's value can be changed by multiple threads. This keyword is essential in multithreaded programming, as it ensures that changes made by one thread are visible to other threads. Why Do We Need Volatile? In a multithreaded environment, each thread has its own local cache of variables. When a thread modifies a variable, the change is first made to the local cache. However, this change may not be immediately visible to other threads, as they may still be using their own cached values. This can lead to inconsistent results and unexpected behavior. The volatile keyword solves this problem by ensuring that changes made by one thread are immediately visible to all other threads. When a variable is declared as volatile , the JVM ensures that: Changes made by one thread are immediately written to the main memory. Other threads always read the variable's value from the main memory, rather than their local...

Java is an object-oriented programming language that supports the concept of static members. In this tutorial, we will explore the concept of static in Java, including static variables, methods, blocks, and classes. What is Static in Java? In Java, the static keyword is used to declare a member that belongs to a class, rather than an instance of the class. This means that a static member is shared by all instances of the class and can be accessed without creating an instance of the class. Static Variables A static variable is a variable that is shared by all instances of a class. It is initialized only once, when the class is loaded into memory. Here is an example of a static variable: public class MyClass { public static int myVariable = 10; public static void main(String[] args) { System.out.println(MyClass.myVariable); // prints 10 } } Static Methods A static method is a method that belongs to a class, rather than an instance of the class. I...

The strictfp keyword in Java is used to restrict the precision and rounding of floating point calculations to ensure portability. It can be applied to methods, classes, and interfaces. What is the Purpose of strictfp? The primary purpose of strictfp is to ensure that floating point calculations are performed in a consistent manner across different platforms. This is particularly important in applications where precise control over floating point calculations is required, such as in scientific simulations or financial calculations. How Does strictfp Work? When the strictfp keyword is applied to a method or class, it restricts the precision and rounding of floating point calculations to the IEEE 754 standard. This means that calculations are performed using the same precision and rounding rules as the IEEE 754 standard, regardless of the underlying hardware or platform. Example of Using strictfp public class StrictFPExample { public static void main(String[] args...

The 'super' keyword in Java is used to refer to the immediate parent class of a subclass. It is used to access the members (methods and fields) of the parent class. The 'super' keyword is particularly useful when we want to override a method of the parent class in the subclass, but still want to call the parent class's method from the subclass. Why Use 'super'? There are several reasons why we might want to use the 'super' keyword in Java: To access the members of the parent class that are not accessible directly in the subclass. To override a method of the parent class in the subclass, but still want to call the parent class's method from the subclass. To call the constructor of the parent class from the subclass. How to Use 'super'? The 'super' keyword can be used in the following ways: 1. To Access Members of the Parent Class public class Animal { public void sound() { System.out.println(...

The Java switch statement is a multi-way decision-making statement that allows you to execute different blocks of code based on the value of a variable or expression. In this tutorial, we will cover the basics of the switch statement in Java, including its syntax, examples, and best practices. Syntax of Switch Statement in Java The syntax of the switch statement in Java is as follows: switch (expression) { case value1: // code to be executed if expression equals value1 break; case value2: // code to be executed if expression equals value2 break; ... default: // code to be executed if expression does not equal any of the above values break; } In the above syntax: expression is the value that you want to compare with the values in the case statements. value1 , value2 , etc. are the values that you want to compare with the expression. break is used to exit the switch statement and continue ex...

In Java, the `synchronized` keyword is used to ensure that only one thread can access a shared resource at a time. This is crucial in multithreaded programming, where multiple threads are executing concurrently and accessing shared data. Why Do We Need Synchronized? In a multithreaded environment, threads may interfere with each other when accessing shared resources. This can lead to inconsistent results, data corruption, or even crashes. Synchronization helps prevent these issues by ensuring that only one thread can access a shared resource at a time. Types of Synchronization There are two types of synchronization in Java: **Method-level synchronization**: This type of synchronization is applied to an entire method. When a thread enters a synchronized method, it acquires a lock on the object that the method belongs to. No other thread can enter the same method until the lock is released. **Block-level synchronization**: This type of synchronization is applied to a ...

A package in Java is a collection of related classes, interfaces, and sub-packages. It is used to organize and structure the code in a way that makes it easier to maintain and reuse. In this tutorial, we will learn how to create and use packages in Java. Why Use Packages? Packages are useful for several reasons: Organization: Packages help to organize the code in a way that makes it easier to find and use the classes and interfaces that you need. Reusability: Packages make it easier to reuse code by providing a way to group related classes and interfaces together. Name Space: Packages provide a way to avoid naming conflicts by providing a unique namespace for each class and interface. Creating a Package To create a package in Java, you need to use the package keyword followed by the name of the package. For example: package com.example.mypackage; This statement should be the first statement in the Java file, before any import statements or class definiti...

In Java, the private access modifier is used to restrict access to a class, method, or variable. It is the most restrictive access modifier in Java, and it is used to hide the implementation details of a class from other classes. What is the Private Access Modifier? The private access modifier is used to declare a class, method, or variable that can only be accessed within the same class. It is not accessible from any other class, including subclasses. Declaring Private Members To declare a private member, you use the private keyword before the member declaration. For example: public class MyClass { private int myVariable; // private variable private void myMethod() { // private method System.out.println("This is a private method"); } } Accessing Private Members Private members can only be accessed within the same class. If you try to access a private member from another class, you will get a compiler error. public class MyClass { ...

The protected access modifier in Java is used to restrict access to a class, method, or variable. It is more accessible than the default modifier but less accessible than the public modifier. In this tutorial, we will explore the protected access modifier in Java, its usage, and examples. What is the Protected Access Modifier? The protected access modifier is used to declare a class, method, or variable that can be accessed within the same package and by subclasses in other packages. It is a way to provide a level of encapsulation and abstraction in object-oriented programming. Access Levels in Java Java has four access levels: Public : Accessible from anywhere Protected : Accessible within the same package and by subclasses in other packages Default (no modifier): Accessible within the same package Private : Accessible only within the same class Using the Protected Access Modifier To use the protected access modifier, you can declare a class, method, or...

The public access modifier in Java is used to declare classes, methods, and variables that can be accessed from any other class. This means that a public class can be instantiated from any other class, a public method can be called from any other class, and a public variable can be accessed from any other class. Declaring Public Classes A public class can be declared using the public keyword before the class name. Here is an example: public class MyClass { // class body } A public class can be instantiated from any other class, regardless of the package it belongs to. However, if the class is not public, it can only be instantiated from within the same package. Declaring Public Methods A public method can be declared using the public keyword before the method name. Here is an example: public class MyClass { public void myMethod() { // method body } } A public method can be called from any other class, regardless of the package it belongs to...

Importing in Java is a way to include classes, interfaces, and other types from other packages into your current program. This allows you to use the functionality provided by these external types without having to rewrite the code yourself. Why Import in Java? Importing in Java is necessary because Java is an object-oriented language that organizes its classes and interfaces into packages. When you want to use a class or interface from another package, you need to import it into your current package. This helps to: Avoid naming conflicts between classes and interfaces with the same name in different packages. Make your code more readable by avoiding the need to use fully qualified names for classes and interfaces. Improve code organization and structure by separating related classes and interfaces into different packages. Types of Imports in Java There are two types of imports in Java: 1. Single-Type Import A single-type import imports a single class or inte...

The instanceof operator in Java is a binary operator used to test if an object (left operand) is an instance of a class, subclass, or implementation of an interface (right operand). It returns true if the object is an instance of the class, subclass, or implementation of the interface, and false otherwise. Syntax The syntax of the instanceof operator is as follows: (object) instanceof (class/interface) Example Usage Here's an example of using the instanceof operator to check if an object is an instance of a class: public class Animal { public void sound() { System.out.println("The animal makes a sound."); } } public class Dog extends Animal { public void bark() { System.out.println("The dog barks."); } } public class Main { public static void main(String[] args) { Animal animal = new Animal(); Dog dog = new Dog(); System.out.println(animal instanceof Animal); // true System....

Java is a statically-typed language, which means that the data type of a variable is known at compile time. In this tutorial, we will explore the int data type in Java. What is int in Java? The int data type in Java is a 32-bit signed two's complement integer. It is used to store whole numbers, both positive and negative, within a specific range. Range of int in Java The range of int in Java is from -2,147,483,648 to 2,147,483,647. This is because the int data type is a 32-bit signed integer, which means it has 32 bits to store the value. One bit is used to represent the sign of the number (positive or negative), and the remaining 31 bits are used to represent the magnitude of the number. Declaring and Initializing int Variables To declare an int variable in Java, you use the int keyword followed by the name of the variable. You can also initialize the variable with a value at the time of declaration. // Declare an int variable int myInt; // Initialize an int v...

Java interfaces are abstract classes that define a contract or a set of methods that must be implemented by any class that implements it. In this tutorial, we will learn about the basics of Java interfaces, how to define and implement them, and their use cases. Defining an Interface An interface in Java is defined using the `interface` keyword. Here is an example of a simple interface: public interface Printable { void print(); } In this example, we define an interface called `Printable` with a single method `print()`. Any class that implements this interface must provide an implementation for the `print()` method. Implementing an Interface To implement an interface, we use the `implements` keyword. Here is an example of a class that implements the `Printable` interface: public class Document implements Printable { @Override public void print() { System.out.println("Printing a document..."); } } In this example, we define a cl...

In Java, the long data type is a 64-bit two's complement integer. It is used to store whole numbers that are too large to be represented by the int data type. The long data type is commonly used when working with large numbers, such as database IDs, timestamps, or financial calculations. Declaring and Initializing long Variables To declare a long variable in Java, you use the long keyword followed by the variable name. You can initialize the variable with a value using the assignment operator (=). long myLong = 1234567890L; Note that when assigning a value to a long variable, you must append the suffix L to the value. This tells the compiler that the value is a long literal. Example Use Cases for long Here are some examples of when you might use the long data type in Java: Database IDs: When working with large databases, you may need to store IDs that exceed the range of the int data type. Timestamps: When working with dates and times, you may need to store t...

Java is a constantly evolving programming language, with new features and updates being added regularly. In this tutorial, we'll take a look at some of the latest additions to the Java ecosystem, including new language features, APIs, and tools. Java 17: The Latest Release Java 17, also known as Java 17 LTS (Long-Term Support), is the latest release of the Java platform. It was released in September 2021 and includes a number of new features and improvements, including: Sealed Classes : A new type of class that can be extended by a fixed set of subclasses, providing a way to restrict inheritance. Pattern Matching for Switch Expressions : An extension of the switch expression feature introduced in Java 14, allowing for more expressive and concise code. Text Blocks : A new way of representing multiline string literals, making it easier to work with large blocks of text. Vector API : A new API for working with vectors, providing a way to perform operations on large datas...

In Java, the 'extends' keyword is used to create a new class that is a modified version of an existing class. This process is known as inheritance. The new class, also known as the subclass or derived class, inherits all the fields and methods of the existing class, also known as the superclass or base class. Why Use 'extends' in Java? The 'extends' keyword is used to promote code reusability and facilitate the creation of a hierarchy of related classes. By inheriting the properties and behavior of a superclass, a subclass can build upon the existing functionality and add new features or override the existing ones. Example of Using 'extends' in Java // Animal.java (Superclass) public class Animal { private String name; public Animal(String name) { this.name = name; } public void eat() { System.out.println(name + " is eating."); } public void sleep() { System.out.println(name + ...