When you're starting to learn a new programming language, it's important to understand what it can do and why it's useful. Java is a programming language that was created after other languages like C and C++. It's like a toolbox that software developers can use to build all sorts of computer programs. Right now, Java is one of the most popular programming languages in the world. Big companies like Amazon, Google, TCS, and Wipro use a lot of Java code. Java comes with many useful features. Let's talk about some of the most important ones:
- Simple: Java was made to be easy for professional developers to learn and use. If you already know a bit about programming, you won't find Java too hard to understand.
- Secure: Java is designed to keep your programs safe. It makes sure that your programs can't mess with other parts of your computer.
- Portable: This means that code written in Java can run on different types of computers and systems. When you write a Java program, it gets turned into something called "bytecode." This bytecode can run on any computer that has a special program called Java Virtual Machine (JVM).
- Object-Oriented: Java is all about using "objects." These are like building blocks for your programs. It's a way of organizing and creating software.
- Robust: Java programs are built to be strong and reliable. It's really good at managing memory, which can be a tricky thing in other programming languages.
- Architecture Neutral: Java was designed so that your programs will work well even when systems change or get upgraded. This way, you don't have to worry about your program suddenly not working because of changes in the computer.
- Distributed: Java is great for making big programs that work across different computers connected to a network. It knows how to communicate over the Internet.
- Dynamic: Java programs can change and update themselves while they're running. This is useful for making sure your program is always up-to-date.
How Java Programs Work
When you write a Java program, there are a few steps to make it run:- Java Program Compilation: Your program gets turned into a special kind of file called "bytecode." This bytecode is like a set of instructions for the computer.
- Java Program Execution: To actually run your program, you need some tools. There's something called a "classloader" that loads your program, a "bytecode verifier" that checks if your program is safe, and an "interpreter" that reads the bytecode and makes your program run step by step.
Java Virtual Machine (JVM)
The JVM is like a virtual computer that understands and runs your Java programs. It's part of something called Java Runtime Environment (JRE), which is like a package that includes the JVM and other important things.Java Development Kit (JDK)
The JDK is a package that helps you create and run Java programs. It includes tools like a private JVM, a compiler, and more, to help you develop your Java applications.Difference between Java and C++
C++ and Java are both programming languages, but they have some differences:- Domain and Usage: C++ is mostly used for building system-level programs, while Java is used for making desktop, web, and mobile applications.
- Compiler and Interpreter: C++ programs are compiled into machine code, making them dependent on the platform. Java programs are turned into bytecode and interpreted by the JVM, making them platform-independent.
- Pointers: C++ uses pointers for memory, which can be tricky. Java uses pointers internally, but you can't directly work with them like in C++.
- Thread Support: Java has built-in support for working with multiple tasks at the same time (threads). C++ doesn't have this built-in; you need extra tools.
- Documentation Comment: Java has a special way to write comments that help keep your code organized. C++ doesn't have this feature.
- Call by value and reference: Java can only pass values to functions, while C++ can pass both values and references.
- Operator Overloading: C++ allows you to create your own meanings for operators, while Java doesn't have this feature.