1. Introduction to Java:
- Java is a popular, object-oriented, high-level programming language developed by Sun Microsystems (now owned by Oracle) in the mid-1990s.
- Known for its “write once, run anywhere” (WORA) philosophy, enabling platform independence through the use of the Java Virtual Machine (JVM).
1.1. Java Virtual Machine:
- JVM is a crucial component of the Java platform that enables Java bytecode to be executed on various hardware and operating systems.
- It acts as an interpreter between the platform-independent Java bytecode and the underlying system.
- Example: When you run a Java program, the JVM translates the bytecode into machine code specific to your operating system and executes it.
1.2. Java Development Kit (JDK):
- The JDK is a software development kit that includes all the tools required to develop, compile, and debug Java applications.
- It contains the Java compiler (javac), JVM, standard libraries, and other development utilities.
- Example: Developers use the JDK to write Java code and create executable Java applications.
1.3. Java Runtime Environment (JRE):
- The JRE is a subset of the JDK and includes only the JVM and essential class libraries needed to run Java applications.
- It is intended for end-users who only need to run Java applications, not develop them.
- Example: When you install a Java application on your computer, you also need to have the JRE to execute the application.
1.4. Integrated Development Environment (IDE):
- An IDE is a software application that provides comprehensive tools and features to facilitate the development of software.
- IDEs enhance productivity by offering code editing, debugging, testing, and project management capabilities in one integrated environment.
- Example: Eclipse, IntelliJ IDEA, and NetBeans are popular Java IDEs that provide code auto-completion, refactoring, and debugging features to help developers write Java code efficiently.
Example Java Code Snippet (Hello World):
```java
Public class HelloWorld {
Public static void main(String[] args) {
System.out.println(“Hello, World!”);
}
}
```
Note: The above code is a basic Java program that prints “Hello, World!” to the console. It demonstrates the syntax of a simple Java class and the `main` method, which serves as the entry point of the program.
