Java is a term that hardly needs any introduction. One of the most widely used programming languages in the world, Java is a powerful programming environment that is used for developing cutting-edge, enterprise-level applications. This language was invented by James Gosling and Sun Microsystems in 1991, and since then, has witnessed tremendous growth. Basically, it is a high-level programming language that allows software developers to write once and run everyone, meaning that the code written and compiled in a specific environment can run on all platforms irrespective of computer architecture.
Though many powerful programming languages have been introduced over the years and growing in popularity, Java still remains the language of choice among many companies. It possesses a number of unique features and is undoubtedly one of the fastest and secured programming languages. If you are starting a career in the IT industry, then becoming familiar with Java basics is a must. Knowledge of this language is considered an important skill for almost all of development-related jobs.
A unique thing about programming languages is that nobody can say he is an expert in any one of them. Similarly, Java is a language that is used for a variety of applications and developers cannot claim they know everything about Java. Generally, the programming concepts are divided into three categories – basic, intermediate, and advanced. Based on this classification, people determine how much do you know about Java or any other programing language.
Now, when you start learning Java, you will obviously start with its basics. But for someone who is new to Java may not know what topics come under the Java basics category. So, in this article, we have described some of the topics that you should cover when you want to gain expertise in Java basics.
Here are the topics one should cover as part of the Java fundamentals.
The Java Platform
There are three major components of the Java platform that are used to build and execute Java programs – the Java Development Kit (JDK), the Java Runtime Environment (JRE), and the Java Virtual Machine (JVM). JDK refers to the tools needed to compile, document, and package Java programs. JRE provides the minimum requirements to execute a Java application. And JVM is a run-time interpreter that executes a Java program line by line.
Object-oriented programming concepts
Java is an object-oriented programming language, which means it follows all the four principles of OOPs – encapsulation, abstraction, inheritance, and polymorphism. In Java, methods and variables are wrapped in a ‘class.’ There are different access modifiers for a class that can restrict the data that can be accessed from it. Moreover, a child class can inherit the properties of a parent class.
Hello World Program in Java
Here is how a Hello World program is written in Java:
public class Sample
public static void main (String [ ] args)
Here, Sample is a class name that we declare at the beginning of the code. The line ‘public static void main (String[ ] args) is where a program starts executing. System.out. println() is the line that prints the text on the console, and the cursor moves to the next line at the console.
Arrays in Java
Basically, an array refers to a data structure that consists of homogeneous elements. Java supports all three types of arrays – one dimensional, two dimensional, and multi-dimensional arrays. Java arrays allow users to access any element randomly through indexes. It is easy to store and manipulate large data sets with Java. However, the size of the array cannot be increased or reduced once it is declared. Also, Java cannot store heterogeneous data in an array.
Classes and Objects
A class can be thought of as a container that stores the data members and methods together. Every class used in Java consists of these components – access modifier, class name, and the body of the class. The object is a closely related concept which is an instance of a class. It includes the real-world entities and manipulates them by invoking methods. A Java object basically consists of Identity, behavior, and state.
A control statement is something that defines the flow of any Java program. Java supports three types of control statements – selection, iteration, and jump. The selection statements consist of if-else and switch case commands. Under iteration, you will read about loops, and Java supports three types of loops – for, while, and do-while. Under Jump statements, you will read about two commands – break and continue. All these statements have specific syntax, and you need to understand how to use them correctly in a program.
If you want to do data manipulation in Java, i.e., storing, searching, insertion, sorting, deletion, or updating of data, then you need to use Collections. It is a pre-defined architecture capable of storing a group of elements and behaving like a single unit like an object or a group. It is the Java Collection framework that offers Java Collection the ability to represent a group of elements in classes and interfaces.
These were some of the important topics that come under Java basics. Go through them one by one to understand everything from scratch. You can also take a Java Basics course if you want to learn Java from an industry expert.