Java Tutorial by Mukesh Sir

 Introduction to Spring Framework In the fast-evolving world of Java development , the Spring Framework has become one of the most reliable and dominant tools for building software. It is known for being powerful , flexible , and easy to integrate , making it a favorite among both beginners and expert developers. Whether you're building a simple web app, an enterprise-level CRM system, or a cloud-native microservice, Spring provides all the tools you need to make your project scalable, maintainable, and modular . What is the Spring Framework? The Spring Framework is an open-source, modular, and lightweight framework designed to simplify the development of Java-based enterprise applications . It was introduced by Rod Johnson in 2002 as a response to the heavy and complex Java EE architecture (like EJB). Today, Spring has evolved into a complete ecosystem that not only supports traditional Java apps , but also REST APIs , cloud-based services , microservices , and reactive pr...

JVM (Java Virtual Machine) JVM (Java Virtual Machine) is an abstract virtual machine that provides a runtime environment to execute Java bytecode. It is platform-independent, meaning the same compiled .class file can run on any device that has a JVM implementation, making Java "Write Once, Run Anywhere" . JVM Working Process Java source code ( .java ) is compiled by the Java compiler ( javac ) into bytecode ( .class file). The JVM loads this bytecode. The bytecode is interpreted or compiled (JIT) into machine-specific instructions . The program runs within the JVM, not directly on the OS. JVM Architecture             +---------------------+             |     Class Loader    |             +---------------------+                      ↓             +---------------------+ ...

 A Java version refers to a specific release of the Java Development Kit (JDK), which includes the Java compiler, runtime libraries, and development tools. Each version brings: New language features Performance improvements Security upgrades API/library enhancements Oracle now follows a 6-month release cycle , meaning a new version of Java is released twice a year — in March and September . Java Version History with Features Java 1.0 (1996) – The Beginning The first official Java release by Sun Microsystems Supported basic OOP features (classes, objects) Included AWT (Abstract Window Toolkit) for GUI development Applets were introduced Java 1.1 (1997) Introduced Inner Classes Added JavaBeans (component model) Introduced Reflection API Improved JDBC (Java Database Connectivity) Java 1.2 (1998) – Java 2 Platform Begins Introduced Swing for GUI Introduced Collections Framework (List, Set, Map) JIT Compiler included Ca...