Section 1.5 The Java Programming Language
The Java programming language was created by James Gosling and his team at Sun Microsystems in the mid-1990s (now owned by Oracle Corporation). The development of Java began in 1991 as a project called "Oak" and was initially intended for use in consumer electronics devices.
However, as time progressed, Java’s focus shifted towards more general-purpose software development and it became widely known for its ability to create platform-independent applications.
The features of Java include the following.
- Simple and Object-Oriented: Java was designed to be a simple and easy-to-learn language. It follows the principles of object oriented programming and provides features such as classes, objects, inheritance, and polymorphism. This makes it suitable for building modular and reusable code.
- Platform-Independence: One of the key features of Java is its "write once, run anywhere" capability. Java programs are compiled into bytecode, which can run on any system with a Java Virtual Machine (JVM). Once the JVM is ported to run on a computational device, programs written in Java, or one of the JVM family of languages, will run on the device. This allows Java applications to be executed on different platforms without the need for recompilation, making it highly portable.
- Robust and Secure: Java was built with a strong emphasis on reliability and security. It includes features like automatic memory management (garbage collection), exception handling, and runtime type checking, which help in writing robust and error-free code. Additionally, Java has a security model that prevents unauthorized access to resources and protects against malicious code execution.
- Rich Core Library: Java comes with a vast and comprehensive core library that provides a wide range of pre-built classes and application programming interfaces (APIs) for common tasks. The core library includes packages for networking, input/output (I/O), data structures, graphical user interfaces (GUIs), and much more. This extensive library reduces the need to write code from scratch and accelerates development.
- Multi-threading: Java has built-in support for multi-threading, which enables the concurrent execution of multiple tasks at the same time on a single processor. Multi-threading enables developers to create efficient and responsive applications. However, proper synchronization mechanisms need to be employed to ensure the safety of threads.
- Garbage Collection: Java’s automatic garbage collection feature relieves developers from manually managing memory allocation and deallocation. The garbage collector automatically detects and removes unreferenced objects, freeing up memory and reducing the chances of memory leaks and crashes.
- Community and Ecosystem: Java has a vast and active developer community, which has contributed to the growth of numerous open-source libraries, frameworks, and tools. This vibrant ecosystem makes it easier for developers to leverage existing solutions and accelerates software development.
Over the years, Java has evolved through various versions, introducing new features and enhancements with each release. The language is used etensively in enterprise software development, web applications, mobile development (Android), scientific research, and more. Java’s versatility, performance, and wide adoption have made it one of the most popular programming languages in the world.
Java is packaged in editions that include a different set of tools tailored for specific purposes and platforms. Java editions include the following.
Java Standard Edition (Java SE). Java SE is the core edition of Java and serves as the foundation for developing general-purpose applications. It provides a robust set of libraries, APIs, and tools for creating desktop, web, and server applications. Java SE includes the Java Development Kit (JDK), which has the necessary tools and resources for Java development.
Java Enterprise Edition (Java EE). Java EE, now known as Jakarta EE, is an extension of Java SE specifically designed for developing enterprise-level applications. It provides an enterprise application framework with additional libraries, APIs, and services to facilitate the development of large-scale, distributed, and scalable applications. Java EE includes features such as web services, messaging, security, and JavaServer Pages (JSP).
Java Micro Edition (Java ME). Java ME is a scaled-down version of Java designed for resource-constrained devices such as mobile phones, embedded systems, and other small devices. It provides a runtime environment and a set of APIs optimized for these devices, enabling developers to create mobile applications and embedded systems with limited resources.
Other Java Editions. In addition to the main editions mentioned above, there are other specialized editions of Java, including Java Card (for running Java applications on smart cards), JavaFX (for building rich client applications with a modern user interface), and Java Embedded (for developing applications for embedded systems and IoT devices).
It’s worth repeating that Java SE forms the foundation of the other editions, and many developers primarily work with Java SE while leveraging specific features or APIs from other editions as needed. We use the Java SE edition throughout this book.
