What Is Java Programming?
Java is a widely used high-level, robust, object-oriented, secure programming language and platform. Java was created in 1995 by Sun Microsystems (now an Oracle company). James Gosling is regarded as the “Father of Java.” It was called Oak before Java by Oracle. The name Oak was changed to Java by Oracle’s James Gosling and his team because Oak was already a registered company. In this article, we will cover the Introduction to java.
Java is an object oriented, case sensitive, class based programming language that is portable and platform-independent, meaning that Java code can run on any device with a Java Virtual Machine (JVM) installed. One of Java’s key advantages is its simplicity and adaptability. It offers straightforward syntax and a big library of built-in functions, making it simple to build code for a wide range of applications, including web development, mobile apps, and business software. Java is also well-known for its reliability, security, and scalability, making it an appealing choice for large-scale applications and projects.
It is used by a wide range of organisations, including big tech companies like Google and Amazon, as well as banks, governments, and universities. Java is often used to create Android mobile apps, server programs, and web applications with frameworks like Spring and Struts. Currently, more than 3 billion devices run on features built in Java .
History Of Java Programming Language
Java is a programming language invented by James Gosling, Mike Sheridan, and Patrick Naughton, a team of Sun engineers known as the Green team in 1991. History of java versions starts with, The first public version, Java 1.0, was released in 1996 and could run on many devices for free. Arthur Van Hoff later rewrote the Java 1.0 compiler in Java to make it more accurate. Later, a new version of Java called Java 2 was released, with different versions for different types of devices.
Sun Microsystems addressed the ISO standards committee in 1997 and later formalized Java, but withdrew from the process shortly thereafter. Despite its proprietary software category, Sun used to make most of its Java implementations available for free. Sun made money on Java by selling licences for specialized products like the Java Enterprise System.
He released a significant portion of its Java virtual machine as free, open-source software on November 13, 2006. Sun completed the process on May 8, 2007, by making all of its JVM’s core code available under open-source distribution guidelines.
Features In Java Programming
Let’s see the various features provided by Java.
1. Object Oriented Programming (OOPs)
Object-oriented programming (OOPs) organizes software design and logic around objects, classes, and data rather than procedures or functions. Object-oriented programming means to leverages real-world techniques to develop application code while keeping data security and integrity at the forefront of design. There are four fundamental pillars of Object-oriented programming, and these are as follows:
- Encapsulation:- It is a term used in Object-Oriented Programming to denote the practice of combining data and its associated functions into a single unit. This is similar to a real-world scenario in a firm, where separate departments such as accounts, finance, and sales conduct specific responsibilities and retain relevant data records.
- Abstraction:- Abstraction means showing only the most important information while obscuring the details. Data abstraction is the process of presenting only essential information about data to the outer world while obscuring the background details or implementation.
- Polymorphism:- Polymorphism is defined as having several forms. Polymorphism is defined as the ability of data to be displayed in more than one form.
- Inheritance:- In Object-Oriented Programming, Inheritance refers to the ability of a class to acquire properties and attributes from another class. It is a fundamental feature that plays a crucial role in designing and implementing object-oriented systems.
2. Platform Independent in Java Programming
In Java programming , the compiler compiles source code into bytecode, which is then executed by the Java Virtual Machine (JVM). A wide range of systems, including Windows, Linux, and macOS, can run this bytecode generated by the compiler because each platform has its own JVM, which generates platform-specific machine code from the same bytecode. As a result, running the same source code on different platforms with different JVMs produces similar results, making Java a platform-independent language.
3. Simple
Java is developed in such a way that it is simple to understand. It is simple to master Java if you understand the fundamentals of OOPs. Furthermore, it lacks complex features such as operator overloading, pointers, multiple inheritances, etc.
4. Java Programming is Safe and Reliable
The fact that we don’t have access to pointers in Java makes it incredibly safe. It is impossible for problems like buffer overflow or stack corruption to arise because we cannot access external arrays due to the lack of pointers.
5. Robust
The Java programming language is robust, which implies it is reliable. It is designed in such a way that it makes every attempt to find errors as early as possible, which is why the Java compiler can detect errors that other programming languages cannot. Garbage collection, exception handling, and memory allocation are the core aspects of Java that make it robust.
6. High Performance
The architecture of Java is designed to minimize runtime overhead. To achieve this, Java sometimes utilizes a Just-In-Time (JIT) compiler, which compiles code on-demand basis. The JIT compiler only compiles those methods that are called during runtime, which results in faster execution of the application.
7. Sandbox Execution
Java applications operate in a distinct environment that enables users to run their programs without impacting the underlying system. This is accomplished by using a bytecode verifier, which ensures that the code is free of errors and enhances security by checking for any unauthorized access.
Java Programming Terminology
Let’s try to understand the various terms frequently used in Java and how the code in Java is executed. The flow chart given below shows how a Java program is executed.
1. Java Virtual Machine (JVM)
JVM is the common name for this. Program execution is divided into three stages. The program is written, compiled, and executed.
- A Java programmer, such as you and I, write programs.
- The JAVAC compiler, a primary Java compiler included in the Java development kit (JDK), performs the compilation. It produces bytecode as output and accepts a Java program as input.
- A program’s JVM runs the bytecode produced by the compiler during the Running phase.
As we have learned, the Java Virtual Machine (JVM) is responsible for running the bytecode generated by the compiler. It is worth noting that each Operating System has its own JVM. However, despite the differences in JVMs, the output generated by executing the bytecode remains consistent across all platforms. This is the reason why Java is widely regarded as a platform-independent language.
2. Bytecode in The Development Process
Bytecode is a platform-independent set of instructions that the JVM understands and executes. When we compile any Java code, the compiler converts it into bytecode. It is equivalent to the assembler in C++. Bytecode is an intermediary level of instructions between the high-level language in which we write code and the low-level machine code that the computer executes. When we write code in a high-level language, it is compiled into bytecode. The JVM then translates the bytecode into a low-level set of instructions.
3. Java Development Kit (JDK)
As the name implies, Java Development Kit is a full-time kit that includes a compiler, Java Runtime Environment (JRE), Debuggers, and Java documentation. We must have JDK installed on our computers in order to create, compile, and run the Java program.
4. Java Runtime Environment (JRE)
The Java Development Kit (JDK) includes the Java Runtime Environment (JRE). Installing JRE on a computer enables the execution of Java programs, but does not provide the ability to compile them. JRE includes JVM, a browser, applet support, and plugins that are necessary for running Java applications. As a result, having JRE installed on a computer is required in order to run Java programs.
5. What is Java Garbage Collector in Java Programming?
In Java, the Java Virtual Machine (JVM) features a Garbage Collector that automatically frees up memory by recollecting items that are no longer referenced in the code. This makes life easier for programmers because they no longer have to manage memory manually. However, programmers must still be careful about what they write in their code and how long they use certain objects because the Garbage Collector cannot recover memory for objects still in use. Garbage collection is a hands-free process that happens automatically.
6. Class Path in Java Programming
The classpath is a specific file path for which both the Java runtime and the Java compiler look for .class files. However, the Java Development Kit includes a large number of libraries by default. You can also have an external set of libraries here, but they must first be added to the classpath.
Writing First Program In Java
To run Java Code on your device, you must install the Java Development Kit (JDK) on your Windows computer. You can download the latest version of the JDK (Java Development Kit) from the Oracle website. After that, you can use any IDE, such as VS Code, Eclipse, Atom etc., to create a .java file to write and run Java programs easily. Let’s see the program in Java for printing “Welcome to Geekster”.
Program
// Importing important classes from packages
import java.io.*;
// Main class
public class Geekster {
public static void main(String[] args)
{
// Print statement
System.out.println("Welcome to Geekster");
}
}
Output
Welcome to Geekster
Explanation
1. Comments:- Comments are used to explain code and are used similarly in Java, C, and C++. Compilers ignore comment entries and do not execute them. Comments might be on a single line or multiple lines.
Syntax
1. For Single Line
// This is comment
2. For Multiple Line
/* This is comment */
2. import java.io:- The “import” keyword in Java includes a class in the code. When we import classes from the “io” package, we get access to input and output streams that allow us to read or write files and input or output.
3. Class:- In Java, a class is a container that holds data and functions for a program. The behaviour of the class is defined by its functions. The class named Geekster has only one function, “Main”.
4. Public Static:- Static methods in Java can be called without creating objects. Instead, they can be executed using the dot operator with the name of the class.
5. Void:- This keyword denotes that the method will not return anything.
6. main():- It is the entry point of our program.
7. System.out.println:- It is used to print the content.
Advantages Of Java Programming
- Platform Independent:- A wide range of systems, including Windows, Linux, and macOS, can run the bytecode generated by the compiler because each platform has its own JVM, which generates platform-specific machine code from the same bytecode. This makes Java a platform-independent language.
- Simple:- Java is developed in such a way that it is simple to understand. It is simple to master Java if you understand the fundamentals of OOPs.
- Object-oriented Programming:- Java is an object oriented programming language, which implies it follows encapsulation, inheritance, and polymorphism concepts.
- Secure:- Java contains built-in security features that make it a secure environment for developing projects, such as automatic memory management and type checking.
- Significant developer community:- Java has a huge and active developer community, which means a lot of help is available for learning and utilizing the language, making it a good language for development.
Conclusion
- Java is a widely used high-level, case-sensitive, robust, object-oriented, secure programming language and platform.
- James Gosling is regarded as the “Father of Java.”
- Java is an object-oriented, class-based programming language that is portable and platform-independent, which means that Java code can run on any device that has a Java Virtual Machine (JVM) installed.
- Java provides various features such as:
- Object-oriented Programming
- Platform Independent
- Simple
- Safe
- Robust
- High Performance
- The Java Virtual Machine (JVM) is responsible for running the bytecode generated by the compiler. It is worth noting that each Operating System has its own JVM.
- Bytecode is a platform-independent set of instructions that the JVM understands and executes. When we compile any Java code, the compiler converts it into bytecode.
- Java Development Kit is a full-time kit that includes a compiler, Java Runtime Environment (JRE), Debuggers, and Java documentation.
- JRE (Java Runtime Environment) includes a browser, JVM, applet support, and plugins that are necessary for running Java applications.
- The Java Virtual Machine (JVM) features a Garbage Collector that automatically frees up memory by recollecting items that are no longer referenced in the code.
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