Introduction to Java

What is Java?

Java is a high-level, object-oriented programming language developed by Sun Microsystems (now owned by Oracle). It is platform-independent and can run on any device with a Java Virtual Machine (JVM).

Features of Java

  • Platform Independence
  • Object-Oriented
  • Secure
  • Robust
  • Multithreaded
  • High Performance

Setting Up Java

To start writing Java programs, follow these steps:

  1. Download and install the Java Development Kit (JDK) from the Oracle website or OpenJDK.
  2. Set the environment variable PATH to the JDK's bin directory.
  3. Verify installation by opening the command prompt and typing java -version and javac -version.

Writing Your First Java Program

Follow these steps to write and run your first Java program:

Step 1: Create a Java File

Open a text editor and type the following code:

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

Save the file as HelloWorld.java.

Step 2: Compile the Java Program

Open the command prompt, navigate to the directory where you saved the file, and type:

    javac HelloWorld.java

This will generate a HelloWorld.class file.

Step 3: Run the Java Program

In the same directory, type:

    java HelloWorld

You should see the output:

    Hello, World!

Understanding the Code

  • public class HelloWorld: Defines a public class named HelloWorld. The file name must match the class name.
  • public static void main(String[] args): The main method is the entry point of the program.
  • System.out.println("Hello, World!"): Prints "Hello, World!" to the console.

Conclusion

In this tutorial, we introduced Java, set up the environment, and wrote a simple Java program. Explore more by learning Java syntax, loops, and object-oriented programming concepts.




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