Welcome to Java programming! Java is a popular, high-level programming language that's known for its write once, run anywhere capability. It's object-oriented, platform independent, and designed to be secure and robust. This means you can write Java code once and run it on any operating system that has a Java Virtual Machine.
Let's understand how Java works. First, you write Java source code in dot java files. Then, the Java compiler, called javac, compiles your source code into bytecode stored in dot class files. Finally, the Java Virtual Machine, or JVM, executes this bytecode to produce the output. The JDK contains development tools including the compiler, the JRE provides the runtime environment with the JVM, and the JVM is what actually runs your Java programs.
Now let's look at Java's basic syntax and structure. Java follows specific rules: every statement must end with a semicolon, code blocks are enclosed in curly braces, and the language is case-sensitive. You can add comments using double slashes for single lines or slash-star for multi-line comments. All Java code is organized into classes, and every executable program must have a main method as its entry point. Here's a simple Hello World example showing the basic structure.
Java has two main categories of data types. Primitive types are the basic building blocks like int for whole numbers, double for decimal numbers, boolean for true or false values, and char for single characters. Reference types include String for text, arrays, and objects. When declaring variables, you specify the type followed by the variable name and optionally assign a value. For example, int age equals twenty-five creates an integer variable, while String name equals John creates a text variable.
To summarize what we've learned about Java basics: Java is a platform-independent, object-oriented programming language that compiles to bytecode and runs on the Java Virtual Machine. It follows specific syntax rules using semicolons and braces, organizes code into classes, and supports both primitive and reference data types. These fundamentals provide a solid foundation for building robust, cross-platform applications.