Best Java Tutorial – Learn Java from Core to Advanced for 2019

Do you want to learn Java? Want to become an expert in Java? And still looking for the best Java tutorial? This Java tutorial is specially designed for beginners. Here, you will get all the basic information of the Java programming language. Here, is a quick overview of this Java tutorial for beginners.
  1. Introduction to Java programming with its features?
  2. Architecture & Application
  3. Advantages & Disadvantages
  4. C++ Vs Java

So, are you excited to explore Java tutorial for Beginners?

Learn Java Programming

1. What is Java Programming Language?

Widely used to introduce students to the world of programming, Java is a general-purpose programming language with uses as many as napkins in a magician’s pocket. More formally, it is a programming language that is concurrent, class-based, and object-oriented.

It follows the principle of WORA (Write Once, Run Anywhere), and is platform-independent. It is also simple and easy to learn. If you wanted to print something (say, “Hello, World!”), you would type:

Java Hello World Example-

public class Hello{
public static void main(String[] args){
System.out.println("Hello, World!");
}
}

Check out Latest Java Infographic for Beginners

2. History of Java Language

Java is a popular name today in every engineering institute and even in schools. But let’s first take a look at how it came into existence.

  • Java first appeared in 1995 as Oak. This was a reference to the Oak tree that stood afar Gosling’s office. Before it could find its popularity as Java (finding its roots in coffee, which in turn is attributed to Java- an island in Indonesia), they also decided to call the project Green.

Java Founder James Gosling

James Gosling, founder of Java

  • Version 1.0 rolled out in 1996 when Sun Microsystems promised the principle of WORA (Write Once, Run Anywhere).
  • Then came along Java 2 (J2SE 1.2) in December 1998-1999. J2EE was for enterprise applications.
  • Then in 2006, boosting its marketing capabilities, Sun renamed new J2 versions as Java EE, Java ME, and Java SE.
  • September of 2018 marked the release of Java SE 11 (LTS).
  • By March of 2019, Java SE 12 will get to see the light of day.

Duke

Duke, the mascot

While they originally designed it for interactive television, they soon realized it was way too advanced for the digital cable TV industry at the moment. Today, from web applications and desktop GUI’s to the Internet of Things and self-driving cars- Java is everywhere.

3. Features of Java Programming

Speaking of its popularity, let’s find out what makes it worth it. In this Java tutorial for beginners, we will discuss a list of powerful features of Java programming language:

Features of Java-

  1. Simple
  2. Object-oriented
  3. High-Performance
  4. Secured
  5. Architecture – Neutral
  6. Portable
  7. Platform Independent
  8. Robust
  9. Dynamic
  10. Multithreaded
  11. Distributed

i. Simple

While Java is verbose, it has a syntax similar to C++. This makes it easier to transition from C++ to Java.

It also removes rarely-used features like operator overloading and explicit pointers.
Other than that, it also provides automatic garbage collection so you don’t need to delete unreferenced objects manually.

It is safe to say Java is a simple language.

ii. Object-oriented

Java focuses on objects rather than processes. Java follows the principles of Object-Oriented Programming (OOP):

  • Objects
  • Classes
  • Inheritance
  • Encapsulation / Data hiding
  • Abstraction
  • Polymorphism

Note- Java isn’t a purely object-oriented language, as it does allow primitive data types.

iii. Platform-independent

Languages like C and C++ compile into platform-specific machines. Java, however, follows the principle of WORA (Write Once, Run Anywhere). This means we only ever need to write code once to be able to run it on multiple platforms (hardware or software environments). What makes this possible is that Java code compiles into bytecode, which is platform-independent. You can run it on Windows, Linux, Mac OS, etc.

iv. Portable

Speaking of bytecode, Java is portable because you can carry bytecode over to any other platform it runs on.

v. Robust

The following features make Java strong and powerful:

  • Strong memory management
  • No explicit pointers
  • Automatic garbage collection
  • Exception handling and type-checking mechanisms

vi. Secure

  • As we said in the previous section, the lack of pointers makes Java powerful and secure.
  • It is also true that Java programs run inside a virtual machine sandbox.
  • The JRE (Java Runtime Environment) has a Classloader to dynamically load classes into the JVM (Java Virtual Machine). It separates the package for the classes of the local file system imported from networks; this adds to the security.
  • The Bytecode Verifier inspects fragments of code for illegal code that can bypass access.
  • The Security Manager decides what resources to allot to a class. Such access can include reading and writing files.

Java can help you develop virus-free systems.

For more features – refer this Java Features Infographic

4. Java Architecture – The Java Environment

In this section of the Java tutorial, we will see Java ships with a set of development tools.

Learn Architecture of Java

a. JVM (Java Virtual Machine)

The Java Virtual Machine is a (virtual) machine. Its purpose is to provide a runtime environment in which to execute bytecode. It is platform-dependent, and has the following tasks:

  • Load code
  • Verify code
  • Execute code
  • Provide a runtime environment

b. JRE (Java Runtime Environment)

This is a collection of tools that together allow the development of applications and provide a runtime environment. The JVM is a part of this. This, like the JVM, is platform-dependent.

c. JDK (Java Development Kit)

Along with the JRE (which includes the JVM), JDK contains other resources like the interpreter/loader (java), the compiler (javac), an archiver (jar), and a documentation generator (Javadoc). Together, these components form the whole development kit to help you build with Java.

Also, see the Difference between JDK, JRE, and JVM

5. The Architecture of the JVM

As a Java beginner, you should know the architecture of the Java virtual machine. Let’s dig a little deeper into JVM.

Learn Architecture of Java Virtual Machine

Classloader – It loads class files. Java has 3 built-in classloaders:

  • Bootstrap ClassLoader
  • Extension ClassLoader
  • System/Application ClassLoader

Class Area – This store class structures like the runtime constant pool, and the field and method data.

Heap – This is the area in which data is allocated at runtime.

Stack – This holds local variables and intermediate results. It also serves for method invocation.

PCR – The Program Counter Register holds the current instruction’s address – the one that is being executed.

Native Method Stack – This consists of the native methods of the application.

Execution Engine – This consists of an interpreter, a virtual processor, and the JIT (Just-in-Time) compiler. The JIT compiles a called method’s bytecode just in time; it is activated when we call the method.

Java Native Interface – Abbreviated as JNI, this is a framework that acts as an interface to communicate with another application in a language like C++ or Assembly.

Do you know How to Install Java in Windows and Linux?

6. Advantages and Disadvantages Java

Always two sides to the coin. Let’s discuss what makes Java great, and what doesn’t- shall we? This section of Java tutorial, we will cover all the strength and weakness of Java language.

i. Benefits of Java Programming

Almost all features of Java make for advantages:

  • Simple; the mild learning curve
  • Platform-independent
  • Object-oriented
  • Secure
  • Distributed
  • Multithreaded
  • Robust
  • High-level language
  • Automatic memory management
  • Large community

Explore the  Advantages and Disadvantages of Java Programming Language

ii. Limitations of Java Language

Java has the following limitations:

  • Being a high-level language that must deal with the compilation and abstraction levels of a virtual machine, Java exhibits poor performance. Other reasons for this are the garbage collector, bad caching configuration, and deadlocks, among others.
  • Java has very few GUI builders – Swing, SWT, JSF, and JavaFX are the more popular of those. Many of these are not consistent/mature enough.
  • Java is verbose. To write code to carry out a simple set of activities, you could end up writing long, complicated code. This can affect readability but ensures that programmers type in exactly what needs to be done. When we compare Java to Python, we observe Python does not need semi-colons, parentheses, or curly braces, and has a visibly shorter code.

7. Difference Between C++ and Java

We said Java has similar syntax to C++. Let’s see what makes it different, then.

  • Java does not support explicit pointers (only internal ones).
  • Unlike C++, Java does not support “goto” statements.
  • Java does not support operator overloading.
  • Although it is possible to exercise multiple inheritances in Java, it has to be through interfaces, and not through classes.
  • Java does not allow “call-by-reference”; it only supports “call-by-value”.
  • Java has no support for structures and unions (as in C++).
  • It does not support the “virtual” keyword. Non-static methods are virtual by default.
  • Java has built-in support for threads, unlike C++.
  • Java supports documentation comments.
  • It supports the unsigned right-shift operator (>>>) to fill in a 0 at the top for negative numbers.

Let’s compare the hello world program in C++ and Java.

Example of C++ Programming Language-

#include <iostream>
using namespace std;

int main()
{
cout << "Hello, World!";
return 0;
}

Explore differences in Java and C++

Example of Java Programming Language-

Now, let’s see how Java compares.

public class Hello{
public static void main(String[] args){
System.out.println("Hello, World!");
}
}

7. Applications of Java Programming

Java is omnipresent. That said, the following are some of the areas it finds use in:

  1. Desktop applications
  2. Web applications
  3. Mobile applications (Android)
  4. Cloud computing
  5. Enterprise applications
  6. Scientific applications
  7. Operating Systems
  8. Embedded systems
  9. Real-time software
  10. Cryptography
  11. In industries like banking, retail, telecom, stock trading, space exploration, oil rigs, and more
  12. Smart cards
  13. Computer games
  14. Web servers and application servers

8. Java Platform Editions

In this part of the Java tutorial, we will discuss the Java platform edition:

  1. Micro Edition – J2ME (Java ME)
  2. Standard Edition – J2SE (Java SE )
  3. Enterprise Edition – J2EE (Java EE )
  4. Java Card

a. Java ME (Micro Edition – J2ME)

This is useful when developing for small devices like mobile phones. The Java ME API is a subset of the Java SE API.

b. Java SE (Standard Edition – J2SE)

This is the one you speak of when you say the word “Java”. The Java SE API holds the core functionality of Java – from basic types and objects to high-level classes for GUI, database access, networking, and security.

c. Java EE (Enterprise Edition – J2EE)

This one is built on top of Java SE. It delivers an API and a runtime environment for the development and running of large-scale, secure network apps.

d. Java Card

This edition lets us build for smart cards using Java.

Java Quiz

9. Top Companies using Java

When we say Java is an immensely popular language, we aren’t simply talking of freshers. The following big names still use Java to build or improve their products and services:

  1. Airbnb
  2. Uber
  3. Google
  4. Intel
  5. Spotify
  6. Accenture
  7. Linkedin
  8. eBay
  9. Pinterest
  10. Groupon
  11. Spotify
  12. Infosys
  13. TCS
  14. Wipro
  15. HCL
  16. Naukri
  17. Jabong
  18. Myntra
  19. Flipkart
  20. Trivago
  21. Ibibo
  22. TripAdvisor

..and many more

10. Summary for Java Tutorial

Java is the king of all programming languages. In the TIOBE index, we can see Java holds the 1st position from last 2 years. Java is not only used for developing applications, but we can also use Java in Big Data, networking, Data Science etc.

In this Java tutorial for beginners, we took a brief look at the Java programming language. We observed its features, pros, and cons, and saw how it compares to a language like C++. We saw its applications and the various editions it ships in. Hope, you found it useful. You may also see the best Java career opportunities.

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