Welcome to Java programming! Java is a powerful, high-level programming language created by Sun Microsystems, now owned by Oracle. It's designed to be simple, robust, secure, and most importantly, platform-independent. This means you can write Java code once and run it anywhere that has a Java Virtual Machine installed.
Java is fundamentally object-oriented. This means everything in Java revolves around objects. You start by defining classes, which are like blueprints or templates. From these classes, you can create multiple objects, which are actual instances that contain data and behavior. This approach makes code more organized, reusable, and easier to maintain.
One of Java's most powerful features is platform independence. When you write Java source code, it gets compiled into bytecode, not machine code. This bytecode is platform-neutral and can run on any operating system that has a Java Virtual Machine installed. Whether it's Windows, Linux, or Mac, the same bytecode will execute identically, making Java truly portable.
Let's look at the basic structure of a Java program. Every Java program must have at least one class. The execution starts from the main method, which has a specific signature: public static void main with String array args. Inside the main method, you write your program logic. This simple Hello World example shows the fundamental structure that every Java program follows.
Java's versatility makes it suitable for many different types of applications. It's heavily used in enterprise software development, powering large-scale business applications. Android mobile apps are built using Java. Web applications often use Java on the server side. Big Data technologies like Hadoop and Spark are written in Java. It's also used in scientific computing and research applications. To get started with Java, you'll need to install the Java Development Kit, or JDK, which includes everything you need to write, compile, and run Java programs.