Java is a high-level, object-oriented programming language that is designed to be platform-independent. It was first released by Sun Microsystems in 1995 and is now owned by Oracle Corporation. Java is widely used for developing a variety of applications, including web, mobile, desktop, and enterprise applications.
Here are some key features of Java:
- Platform Independence: Java code is compiled into bytecode, which can be executed on any platform that has a Java Virtual Machine (JVM) installed. This makes Java programs highly portable, as they can run on different operating systems without modification.
- Object-Oriented: Java is a fully object-oriented language, meaning everything is an object. It supports features like encapsulation, inheritance, and polymorphism, which make it easier to create complex software systems.
- Memory Management: Java provides automatic memory management, which means the developer doesn't have to worry about allocating and deallocating memory for objects. The garbage collector automatically frees up memory that is no longer needed.
- Multi-threading: Java supports multi-threading, which allows multiple threads to execute concurrently within a single program. This makes it easier to create responsive applications that can handle multiple tasks simultaneously.
- Standard Library: Java comes with a comprehensive standard library that provides a wide range of functionality, including networking, input/output, data structures, and more. This makes it easier to write complex applications without having to reinvent the wheel.
- Security: Java has a strong security model that includes a security manager and a sandbox environment. This makes it possible to run untrusted code safely, which is important for applications that need to be deployed over the internet.
Java is widely used in a variety of fields, including web development, mobile development, game development, scientific computing, and more. It is also used for developing enterprise applications, as it provides robust support for distributed computing and web services. Java has a large and active developer community, which means there are many resources available for learning and using the language.
How to Install Java in our PC?
Here is a step-by-step guide on how to install Java on your computer:
- Check if Java is already installed on your computer: To check if you already have Java installed, open a command prompt or terminal window and type the following command: ( java -version ) :- If you see a message that includes the version number of Java, then it is already installed. If you get an error message, then you need to install Java.
- Download the Java Development Kit (JDK): Go to the Oracle Java SE Downloads page (https://www.oracle.com/java/technologies/downloads/) and download the appropriate JDK for your operating system. You should choose the version of Java that matches the architecture (32-bit or 64-bit) of your operating system.
- Install the JDK: Once the download is complete, run the installation program and follow the on-screen instructions to install the JDK on your computer. Make sure to select the appropriate options during the installation process, such as the installation directory and any additional components you want to install.
- Set the Java environment variables: After the installation is complete, you need to set the Java environment variables on your computer. This will allow your computer to locate the Java installation and use it when running Java programs.
For Windows:
- Open the Control Panel and select System and Security.
- Click System and then click Advanced system settings.
- Click the Environment Variables button.
- Under System Variables, find the variable named "Path" and click Edit.
- Add the path to the Java bin directory (e.g. C:\Program Files\Java\jdk-16.0.1\bin) to the list of paths. Be sure to separate it from the other paths with a semicolon.
- Click OK to save the changes.
For Mac or Linux:
- Open a terminal window and enter the following command:-
export PATH=$PATH:$JAVA_HOME/bin
Replace "/path/to/java" with the actual path to the Java installation directory.
- Verify the Java installation: To verify that Java is installed correctly, open a new terminal window and type the following command: ( Java -version ) -If you see the version number of Java, then the installation was successful.
That's it! You have now installed Java on your computer and are ready to start developing Java programs.
Java Quickstart Guide
Here's a quickstart guide to writing and running a Java program:
- Install Java: If you haven't already installed Java, follow the steps outlined in the previous answer.
- Choose a text editor or IDE: You can use any text editor to write Java programs, but an integrated development environment (IDE) can provide helpful features like syntax highlighting, debugging, and code completion. Some popular Java IDEs include Eclipse, IntelliJ IDEA, and NetBeans.
- Write a Java program: Open your text editor or IDE and create a new file. Type the following code into the file:
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, world!");
}
}
This program simply prints "Hello, world!" to the console.
- Save the file: Save the file with a ".java" extension (e.g. "HelloWorld.java").
- Compile the program: Open a command prompt or terminal window and navigate to the directory where the Java file is saved. Type the following command to compile the program:-
This will create a file called "HelloWorld.class" in the same directory.
- Run the program: Type the following command to run the program:
You should see the message "Hello, world!" printed to the console.
Congratulations, you have just written and run your first Java program! From here, you can start exploring the language and its features, such as object-oriented programming, data structures, and more.