Unit-1 Java's Magic PDF

403- Object Oriented Programming with Java Unit-1 Java's Magic Dr. Biren Patel Associate Professor, Department of Computer and Information Technology, HNGU, Patan -- -- What is Java? ============= Java is a high-level, object-oriented programming language developed by **Sun Microsystems** (...

403- Object Oriented Programming with Java Unit-1 Java's Magic Dr. Biren Patel Associate Professor, Department of Computer and Information Technology, HNGU, Patan -- -- What is Java? ============= Java is a high-level, object-oriented programming language developed by **Sun Microsystems** (now owned by **Oracle Corporation**). It was released in **1995** and has since become one of the most widely used programming languages in the world. Brief History of Java --------------------- **1991: The Birth of Java (Project Green)** - Java was originally conceived by James Gosling, Mike Sheridan, and Patrick Naughton under the project name \"Green.\" - The language was initially called Oak, named after an oak tree outside Gosling\'s office. **1995: Java is Officially Released** - Oak was renamed to Java due to trademark issues. - Java was officially launched with the tagline *\"Write Once, Run Anywhere\" (WORA)* to emphasize its platform independence. **1996: Java Development Kit (JDK) 1.0** - The first official version of Java, JDK 1.0, was released. - This version introduced core features like applets and basic APIs. **1997: Oracle Joins the Java Community** - Oracle became a major contributor to the development and adoption of Java. **2006: OpenJDK Released** - Sun Microsystems made Java open source by releasing the OpenJDK under the GNU General Public License. - OpenJDK is released under the **GNU General Public License (GPL)** **2010: Oracle Acquires Sun Microsystems** - Oracle Corporation acquired Sun Microsystems and took over Java\'s development. Features of Java ================ - **Platform Independent:** Java follows the principle of \"write once, run anywhere.\" Programs written in Java are converted into bytecode, which can run on any system with a Java Virtual Machine (JVM), regardless of the operating system or hardware. - **Simple:** Java is easy to learn and use, especially for programmers with experience in C++ or object-oriented programming. Its clean syntax and straightforward structure make it accessible and efficient. - **Object-Oriented:** Java uses an object-oriented approach, focusing on objects and their interactions. It balances flexibility by treating basic data types like integers as non-objects for better performance. - **Robust:** Java ensures reliability by managing memory automatically using garbage collection and reducing errors with strong type checking and exception handling. This makes programs less prone to crashes or bugs. - **Multithreaded:** Java supports multithreaded programming, allowing multiple tasks to run simultaneously. Its built-in tools make it easy to create interactive and efficient applications. - **Interpreted & High Performance:** Java compiles code into bytecode, which runs on the JVM. Performance is boosted with Just-In-Time (JIT) compilers that convert bytecode into machine code as needed. - **Distributed:** Java is built for internet-based environments, supporting TCP/IP protocols and features like Remote Method Invocation (RMI) for executing methods across networks. - **Dynamic:** Java provides run-time information about objects, enabling safe and efficient updates to code. This allows programs to adapt and evolve while running. Java's Magic -- Bytecode ======================== When we write a Java program, it's not directly converted into machine code (executable code), it is translated into **bytecode**. **Java Bytecode** is an intermediate, platform-independent code of a Java program. When a Java source file (.java) is compiled, it is converted into bytecode (.class file) by the **Java Compiler (javac)**. This.class file is known as Bytecode. Bytecode is a set of instructions that is executed (interpreted/run) by the **Java Virtual Machine (JVM)** on various platforms**.** Java Compilation Process ========================