Question

Compare and contrast distributed and non-distributed Java programs.

Short answer

Distributed Java programs leverage multiple computers in a network, offering scalability and fault tolerance, while non-distributed run on a single machine, being simpler but less scalable.

Step-by-step solution

Understand Distributed Java Programs

Distributed Java programs are designed to run on multiple computers in a network, working together to achieve a common goal. These programs utilize Java technologies such as Remote Method Invocation (RMI), Enterprise JavaBeans (EJB), and Java Message Service (JMS). They leverage resources across various machines to improve performance, reliability, or to manage tasks that require large-scale computation. These systems are often used in Cloud computing and microservices architectures, where they facilitate communication between different services.

Understand Non-Distributed Java Programs

Non-distributed Java programs, also known as standalone or monolithic applications, run on a single machine or computer. These programs handle all operations and tasks internally without needing to distribute the task across a network. They might involve user interfaces, databases, and backend processing but all are inclosed within one application framework without external communication. Examples of non-distributed applications are small utilities, games, or applications that run entirely on a user's desktop.

Compare Communication Methods

In distributed Java programs, components communicate over a network using defined protocols, often involving serialization and deserialization of objects. This allows different parts of the application to be located on different network nodes. In contrast, non-distributed programs have all components communicating directly within the same memory space, making them simpler in terms of interaction and coordination.

Contrast Scalability

Distributed Java programs are typically more scalable since they can leverage multiple machines to distribute load and handle increasing amounts of work. They can be easily expanded by adding more nodes to the network. Non-distributed programs are less scalable because all processing is done on a single machine, which limits the program's performance and capacity to the physical resources available on that machine.

Contrast Fault Tolerance

Distributed programs often incorporate fault tolerance mechanisms, as they need to handle potential network failures, machine crashes, or disruptions in communication. This might include redundancy and backup systems. On the other hand, non-distributed programs generally lack such mechanisms because everything runs on a single machine. If this machine crashes, the entire application is impacted.

Key concepts

Java Programming

Java programming is a versatile and widely used language because of its platform independence and object-oriented nature. At its core, Java's "write once, run anywhere" capability means that code written in Java can run on any device with a Java Virtual Machine (JVM). This makes it particularly well-suited for creating both distributed and non-distributed applications.
Java offers a robust API that supports a variety of programming tasks, including graphical user interfaces (GUIs), database connectivity through JDBC, and network communication, among other things. Java’s extensive library allows developers to build complex applications effectively without having to start from scratch.
One of Java’s key features is its focus on security. By running inside the JVM, Java applications have a managed environment that keeps them safe from certain types of malicious activities.

• Platform independence due to JVM.
• Rich standard library and API support.
• Strong focus on security.

Remote Method Invocation (RMI)

Remote Method Invocation (RMI) is a powerful feature of Java that enables an object to invoke methods on an object residing in another JVM. This facilitates distributed computing in Java, as it allows different parts of a distributed application to communicate across a network.
RMI abstracts the complexity of network communication by providing a higher-level, object-oriented API. Developers can interact with remote objects in a manner similar to local objects, thanks to Java's RMI registry which helps locate and execute methods on remote servers.
RMI uses serialization, which is the process of converting an object into a byte stream for transmission over a network. This stream is then deserialized back into a Java object at the receiving end. However, for RMI to work effectively, both client and server must have compatible versions of the classes used.

• Enables remote object interaction across JVMs.
• Supports serialization for data transmission.
• Relies on a central RMI registry for locating remote objects.

Enterprise JavaBeans (EJB)

Enterprise JavaBeans (EJB) is a Java API developed for building scalable, robust, and secure enterprise-level applications. EJB is part of the J2EE (now Jakarta EE) architecture, which provides a standard way to enable the development and deployment of reusable, server-side components.
EJB is particularly useful when building large-scale distributed systems. It supports distributed computing with built-in services such as transaction management, messaging, and security. These services simplify the process of building large enterprise applications by offloading the responsibility of these complex tasks to the EJB container.
One of the key benefits of using EJB is that it allows developers to focus on business logic without worrying about underlying system complexities. This is achieved through various bean types including session beans, entity beans, and message-driven beans, each fulfilling different roles in the application.

• Facilitates the development of transactional and distributed applications.
• Provides built-in services for security and messaging.
• Encourages reuse of server-side components.

Cloud Computing

Cloud computing is a model that offers convenient, on-demand network access to a shared pool of configurable computing resources, such as servers, storage, and applications. This model allows businesses to scale and innovate more efficiently by rapidly provisioning resources, based on demand.
In a Java environment, cloud computing is particularly relevant because Java's platform independence is ideal for deploying applications on diverse cloud solutions. Many cloud providers offer Java-based development environments, with tools like AWS Elastic Beanstalk and Google App Engine supporting Java applications.
Distributed systems benefit greatly from cloud computing, as they often need to manage large volumes of data and computations across several nodes. Cloud platforms offer the flexibility, scalability, and fault tolerance required for such systems, allowing them to grow and adapt dynamically to user demands.

• Offers scalability and resource efficiency.
• Supports Java applications through a variety of cloud-based services.
• Enhances distributed systems with fault-tolerant infrastructure.