Core Java Topics: Mastering the Fundamentals of Java Programming

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Learn about core Java topics in this article. Every Java developer, whether a beginner or an expert, should master several Java topics to ace his programming. Learning programming languages can be demanding, and Java is one of the most challenging languages, with multiple ins and outs that can overwhelm and demoralize the developer.

java programming

However, following the right approach can make the learning task much easy and more playful. There are many advantages to fully comprehending how Java programming functions. It will simplify your life, for instance, if you are coding in Java. Additionally, it will ensure you save time on programming bugs.

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Core Java Topics

A few topics in Java language are the learning benchmarks and are reliable when coding. In this article, we will read the core java topics which can be of great help. This work is in use as a reference guide by the developers to keep a check on their programming knowledge. These concepts are as follows:


The interface should elaborate on the behavior of the object. There are three steps to do so.


  • Firstly, there is a requirement for creating an interface.
  • Secondly, the methods for that interface must define.
  • Lastly, the class is to be written with implementation.

Doing this ensures the flexibility of the code and facilitates its testing in Java.


In lame language, variables are container boxes holding data values. There are three kinds of variables.


Static Variables



Non-static variables


Local Variables


These types of variables can be accessed without any object. These global variables that are declared as “static” create a single copy of the variable and are shared among all the objects at the class level.



These kinds of variables can be accessed by using a class object. These variables are created with the creation of the class object and destroyed with the object’s destruction.


Variables are meant for a particular method of code, and these are formed when a function is called and ceases to exist outside that block.


Variables follow specific rules such as there should be no spaces, should not start with any number, no special symbols except underscore (_), and are case sensitive.



Types of data in Java



Variables to store them

Texts with double quotes strings
Integers (whole numbers without decimals) int
Decimal numbers Float
Single characters with single quotes char
Two different states value Boolean

Objects and classes

First, a class is created with a prototype. This prototype further helps in the creation of the object of the class. The behavior of these objects is determined by the variables and functions used. Objects include state, identity, and behavior. A few factors must be considered to comprehend Java’s relationship between classes and objects. A class is similar to a blueprint used to generate various things.

class and objective

It copies the properties from that class because all objects in one class share the same properties. Since you cannot create objects without a class, every object should be a class member. A type is another name for a class.

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Object-oriented programming endorses the following characteristics:


a. Encapsulation: When you encapsulate anything, you keep all of its crucial details hidden from view from the outside world. Attributes and actions, for instance, are specified by code in the class template.

b. Abstraction: An object is said to be abstracted when the user is only exposed to a subset of its properties and methods.

c. Inheritance:  classes can take on the properties of their parent classes. This is because Inheritance facilitates reusability. In JavaScript, you can think of Inheritance as prototyping.

d. Polymorphism: OOP relies heavily on polymorphism because of its usefulness. With polymorphism, Java can construct objects and entities that can take several forms. In Java, a method is polymorphic if implemented in several ways.

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Java supports two varieties of polymorphism.

When a polymorphic or overloaded method is called, its implementation is determined at compile time. The term “Overloading Polymorphism” refers to a phenomenon that can occur during compile time.


Polymorphism through Overriding – In Java, a call to an overridden method resolves at runtime thanks to runtime polymorphism. Runtime Polymorphism is another name for Overriding Polymorphism.

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What are the core technologies of a Java developer?

A Java developer's core technologies include Java SE (Standard Edition) for basic applications, Java EE (Enterprise Edition) for enterprise-level systems, Spring and Hibernate frameworks for building robust applications, and various tools like Eclipse or IntelliJ IDEA for development.

What are the four pillars of core Java?

The four pillars of core Java are Encapsulation (data hiding), Abstraction (data representation), Inheritance (code reusability), and Polymorphism (ability to take multiple forms). These principles form the foundation of object-oriented programming and facilitate efficient software development.

What are the 5 OOPs concepts?

The five OOPs concepts are Abstraction (representing essential features), Encapsulation (bundling data and methods), Inheritance (creating classes from others), Polymorphism (using one interface for multiple types), and Association (relationship between classes). These concepts enable organized and modular programming in object-oriented languages like Java

What are the three main components of Java?

The three main components of Java are Java Development Kit (JDK), which contains tools to develop and run Java programs; Java Virtual Machine (JVM), which executes Java bytecode; and Java Runtime Environment (JRE), allowing running Java applications without development tools. Together, they facilitate Java's 'write once, run anywhere' principle.


Therefore, These were the following core Java topics that every programmer should be aware of. With the help of these, one can understand Java in a much better way.

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