The full form of UML is “Unified Modeling Language”. It is a general-purpose modeling language. The main aim of UML is to define a standard way to visualize how a system has been designed. It is quite similar to blueprints used in other fields of engineering. UML is not a programming language, it is rather a visual language.

• We use UML diagrams to portray the behavior and structure of a system.
• UML helps software engineers, businessmen, and system architects with modeling, design, and analysis.
• The Object Management Group (OMG) adopted Unified Modelling Language as a standard in 1997. It’s been managed by OMG ever since.
• The International Organization for Standardization (ISO) published UML as an approved standard in 2005. UML has been revised over the years and is reviewed periodically.

What is Unified?

UML aims to provide a standardized way to visualize and design systems, making it easier for different stakeholders to understand and communicate about a system regardless of their backgrounds or the specific domains they work in.

What is Modeling?

Modeling involves creating abstract representations of a system. In the context of UML, modeling refers to creating diagrams and other artifacts that represent different aspects of a software system, such as its structure, behavior, and interactions.

What is Language?

UML provides a set of symbols, notations, and rules for creating models. It’s a formal language that allows developers, designers, and other stakeholders to express their ideas, designs, and requirements using a common set of symbols and semantics.

Types of UML Diagrams

Structural UML Diagrams

These diagrams focus on depicting the static structure of a system, showing the elements that compose the system and how they relate to each other.

Examples of structural UML diagrams include:

• Class Diagram: Illustrates the classes in the system, along with their attributes, methods, and relationships.
• Object Diagram: Shows a snapshot of instances (objects) of classes and their relationships at a specific point in time.
• Component Diagram: Depicts the physical components of a system and their dependencies.
• Package Diagram: Represents the organization of classes into packages and the dependencies between them.
• Composite Structure Diagram: Describes the internal structure of a class or component, including its parts and how they interact.

Behavioral UML Diagrams

These diagrams focus on representing the dynamic behavior and interactions between the components of a system over time.

Examples of behavioral UML diagrams include:

• Use Case Diagram: Illustrates the interactions between actors (users) and the system, focusing on the system’s functionality from a user’s perspective.
• Sequence Diagram: Shows the sequence of interactions between objects or components over time, emphasizing the order in which messages are exchanged.
• Activity Diagram: Represents the flow of activities or processes within a system, including decisions, loops, and parallel activities.
• State Machine Diagram: Describes the various states that an object or component can be in and how it transitions between those states in response to events.
• Communication Diagram: Similar to sequence diagrams, but focuses more on the relationships between objects and their interactions.