This content originally appeared on DEV Community and was authored by JigNect Technologies
Java is one of the most widely used programming languages, known for its versatility, platform independence, and robustness, it remains a favorite among all the developers globally. Whether you are new to programming or wishing to enhance your Java skills, then, it is imperative to understand the basic principles of Java in order to write code that is not only effective and efficient but also easy to maintain.
This blog post is intended to be your guide to learning Java. We will start with the basics of the language, and discuss data types, variables, methods, and constructors. We will then progress to the control flow constructs such as if-else statements, loops and switch cases to enable you develop the logic and the ability to repeat certain blocks of code. But we are not done yet! We will also look at some of the more advanced topics like OOP, collections, and exceptions, so you will have a full understanding of the Java development process.
By the time you finish this guide, you’ll possess a solid Java foundation and be prepared to confidently confront real-world programming obstacles. Let’s get started!
Understanding Datatypes and Variables
In Java, Data types are very important because they determine what kind of information can be stored and used. Primitive data types, such as integers, floating-point numbers, characters, and booleans, provide the foundation for representing simple values.
On the other hand, non-primitive data types, like arrays, classes, and interfaces, enable the creation of more complex structures and allow for the organisation and manipulation of larger sets of data.
A Variable is a container that holds data that can be changed during program execution.You will often define variables for WebDriver instances, element locators, or test data.
Let’s understand this with the Fibonacci series. It is a sequence of numbers where each term is the sum of the two preceding ones, beginning with 0 and 1. The pattern follows: 0, 1, 1, 2, 3, 5, 8, 13, 21, …
The provided Java program generates the Fibonacci series for a predefined number of terms, the variable n of int data type is set to 10 in this example. It utilizes primitive data types, specifically int, to store the first two terms of the series (0 and 1), while an ArrayList serves as a non-primitive data type to dynamically store the generated Fibonacci numbers.
An Overview of Methods and Constructors
Methods are essentially blocks of code that are designed to perform a specific task. A method is grouping of instructions that execute some operation and return the result. It allows us to reuse the code without writing it again.
Let’s consider the example of factorials of the number.
Here, a factorial method is created which returns the factorial of the given number.
This method is called from the main method of the class. Factorial method accepts integer value n and finds the factorial of n.
Constructor used to initialise the objects. Every class has at least one constructor, and if none is defined. Java compiler automatically provides a default constructor. Constructors share the same name as the class and do not have a return type.
Let’s consider an example of palindrome numbers. A palindrome number is a number that remains the same when reversed (e.g., 121, 1331).
In this example, isPalindrome method is created which checks if a given number is palindrome or not. Here, obj1 and obj2 are created under the main method and the constructor takes num parameter as an integer and assigns it to the number instance.
Exploring Control Statements in Java
Control statements allow our program to choose different paths of execution based on certain conditions. The primary control flow statements in Java are if , else , switch , while , do while , and for.
How to Use If and If-Else Statements Effectively
You can perform specific actions depending on whether a certain condition is true or false. It checks a condition and runs a set of instructions if the condition is true; otherwise, it skips those instructions. If you have two sets of instructions and need to run one of them, you should use an if-else statement.
Let’s understand this by checking if the given number is odd or even?
The provided Java program checks whether a number is even or odd using an if-else statement. The condition within the if statement evaluates whether the number is divisible by 2, which indicates that it is even; if this condition is true, it prints a message stating that the number is even. Conversely, if the condition is false (meaning the number is not divisible by 2), the program executes the else block, which outputs that the number is odd.
Working with Nested If-Else Statements
The nested if else statement means using if else statement inside if body or else body. It allows for multi-level decision-making based on multiple conditions.
Let’s consider the AgeCategory program as an example. If the age is greater than 18, the user is classified as an adult. If the age exceeds 65, the user is categorized as a senior citizen; otherwise, they are considered a Teenager and if age is less than 13 then child.
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This content originally appeared on DEV Community and was authored by JigNect Technologies