| Term | Explanation |
| Abstraction |
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| Assertion | Refers to an assertion function which is an essential part of test code. If the input values do not satisfy a particular condition, the test containing the assertion will fail. Example call: "assertEquals(expectedResult, actualResult)". |
| Aware/Unaware | Class A contains a source code reference to class B and is therefore aware of class B. If you only read the source code of class A, you would know that there must be a class B. If there was no such reference, class A would be unaware of class B. |
| Best Practices | Generally accepted guidelines for increasing your programming productivity. Taking them seriously will save you a lot of pain. |
| Concretion | It is the counterpart to "abstraction" and is sometimes called "implementation". In OOP it refers to non-abstract classes that could implement methods of interfaces or abstract classes. A concretion defines the internal workings of these abstract functions by providing the "concrete" code. |
| Constructor Injection | Dependency injection, which is performed by passing a dependency to an instance via a constructor argument. |
| Component |
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| Daemon | A program that runs in the background of a computer system, i.e. without a GUI. |
| Data Structure | A very simple type of class that contains only data and no logic. For example, a class that has only public fields and no methods. Another form is a class with private fields and simple corresponding getters and setters. |
| Dependency | In the context of classes, a dependency is a member field of one class that must be initialized with an instance of another class in order for an instance of the first class to function properly. This initialization is often done by dependency injection. |
| Dependency Cycle | For example, an instance of one class requires an instance of another class to be constructed, and vice versa. So both classes need the other dependency to construct an instance. Therefore, it is impossible to construct either instance at all. Always make sure that the dependency graph looks like a directed acyclic graph. |
| Dependency Injection (DI) | A technique in which the dependencies an object needs are injected from the outside, rather than constructed within the class. |
| Dirty | 1. Messy, unreadable, or poorly designed code is referred to as "dirty code". Often associated with code written "quick-and-dirty" due to the time constraints of a software project. 2. The term comes from the phrase "getting one's hands dirty" and refers to coding work that is considered monotonous, detailed, low-level, or undemanding, but necessary. The term is often used in the context of I/O operations. For example, creating a database transaction, is often done in a similar way and is not considered fun by experienced programmers who have done it many times. High-level design is more exciting because it requires more creativity from the developer and is more intellectually stimulating. |
| Dynamic | Often refers to processes that appear at run time when the code has already been executed and is "running". Examples:
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| Entity | 1. In an object context, this means that two objects of the same type that contain exactly the same values in their fields can be considered equivalent, but are still two separate entities. 2. In the context of software architecture, the term refers to classes that represent the data model of the application. For example, a banking application may have entity classes such as account, order, customer, or employee. They are often built like simple data structures, but may contain additional validation logic to impose logical constraints on their fields. For example, the integer field customer.age must always be between 0 and 120 because this is a logical constraint on the age of people, even though the integer data range is technically much larger. |
| Field Injection | A type of dependency injection that is performed by forcibly injecting a dependency into an instance through the use of reflections that break even the encapsulation of private fields. This type of dependency injection should be avoided. |
| Graphical User Interface (GUI) | A type of user interface that allows the user to interact with the computer by means of graphical elements such as icons, buttons, windows and menus. |
| Inversion of Control (IoC) | Shifts the responsibility for defining the logic and order of dependency injections from the developer to the computer. |
| JavaBean | A design convention for data structures. Usually it means a class that has
Often DTOs and entities follow this convention. |
| Logic | Any code with non-trivial complexity can be called "logic". In contrast, for example, getters and setters have trivial complexity. |
| Magic | "Code that handles complex tasks while hiding that complexity to present a simple interface."[sources] For example, the introduction of an IoC container is often quite simple, but the logic and wiring that goes on in the background is complex. |
| Pain | Something causes pain when someone spends unnecessary effort on a task that could often have been avoided by better code design. |
| Production Code | The counterpart to the Test Code. It contains all the code needed to run the application. |
| Rollback | The process of reverting a system or data to a previous snapshot. |
| Runtime | The period of time during which the code is executed. For example:
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| Separation of Concerns | A principle that says that software should be structured modular, with each module dealing with a different aspect of the program. This is intended to give the software a clear, understandable architecture. |
| Setter Injection | A type of dependency injection, which is performed by passing a dependency to an instance via a setter method argument. |
| Snapshot | A snapshot is a copy of a system or data at a specific point in time. It enables 'rollbacks' that can be used to revert to that state in the future if needed. |
| Spring Bean | A term used in the Spring Framework for an object that is contained in the IoC container to be injected into other beans and/or to receive dependency injections. It is one of many components/beans that are wired together via IoC to form the application when it is started. It should not be confused with JavaBeans. |
| Static | Often refers to processes that depend on non-running code. Examples:
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| Test Code | The counterpart to the Production Code. It is code that checks that the production code works as expected. Test code has no role in the operation of an application. |
| Test-Driven Development (TDD) | A workflow in which the developer implements code in small steps, incrementally and iteratively, defining tests at each iteration. |
| Wiring | The process of generating and injecting dependencies to start an application, performed by the IoC container. |