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44 Cards in this Set
- Front
- Back
Object |
An entity with states(fields) and behavior(shown via methods) |
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Class |
blueprint for an object. contains fields and methods that describe the behavior of an object |
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Types a variables |
Local - declared inside a method, destroyed when method is completed Instance - declared inside a class, but outside any method Class - declared inside of a class, static |
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Constructor |
gets invoked when an object is created. sets state (fields) of object. |
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Static |
Keyword. static variables can be called upon without an instance of its class being created. all instances of class share the same variable |
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Access modifier |
sets access levels for classes, variables, methods, constructors. public, private, protected, default |
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Interface |
An interface is a collection of abstract methods. A class implements an interface, thereby inheriting the abstract methods of the interface. interfaces do not provide any implementation, they are only meant to be implemented. sets up a contract for a class to conform to |
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scope |
refers to section of code where variable can be accessed REFACTOR |
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Overriding |
when a class has the same method as its parent class, but the method body is different. |
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Overloading |
when methods are in the same class with the same name but take in different types and/or different number of argugments |
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reflection |
code examining itself. |
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Encapsulation |
hiding data the technique of making the fields in a class private and providing access to the fields via public methods. |
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Nested Class |
static inner class |
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Downcasting |
when you treat a parent class as a child class Animal animal = new Animal() |
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Super |
keyword used to refer to the immediate parent class |
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primitive datatypes |
int, byte, short, long, boolean, double, float, character. |
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Abstract class |
keyword used to specify that a class should not be instantiated. it is only used to be extended by other classes has no implementation |
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Argument |
data item specified in a method call |
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array |
A collection of data items, all of the same type.
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casting |
conversion from one datatype to another |
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Enumerated type |
type whose legal values consist of a fixed set of constants |
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exception |
an event during program execution that prevents the program from continuing normally |
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exception handling |
a mechanism that handles exceptions to keep the program running normally |
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throw vs throws |
throw is a keyword that allows the user to throw an exception. throws is keyword used in a method declaration that specify which exceptions could be thrown |
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what is a checked exception |
any exception that is caught by the compilerbefore run time. |
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Inheritance |
when a sub class acquires the properties of its parent class Is a relationship |
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Composition |
When you put an object inside another object. Has a relationship |
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SOLID principles |
5 principals of Object Oriented Design Single responsibility - a class should only have one job Open closed - a class should be https://www.google.com/search?client=ubuntu&channel=fs&q=are+exception+runtime+erroreasily extended without modifying the class itself Liskov substitution - every subclass should be substitutable with there parent class Interface segregation - a client should not be forced to use a method or interface they dont use Dependency Inversion - allows for decoupling |
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variable |
used to store and manipulate data |
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implicit conversion |
compiler will automatically convert a type into a higher type int > long |
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casting |
manually converting one type to another type (int) long |
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.this |
used when refering to the current object, allows object to pass itself as a parameter |
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null |
refers to an uncreated object |
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types of test |
System - testing the application as a whole aggregate - testing component (series of classes / methods) unit - testing a single unit of functionality (single method / class with single responsibility) |
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test driven development |
Software dev process of writing test before writing code. using test to help guide the design process |
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test structure |
Given - establish the preconditions for the test When - what is being tested Then - checking the outcome |
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polymorphism |
the ability of an object to take multiple forms |
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abstraction |
technique of hiding implementation details from the user and only providing them with functionality |
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Wrapper class |
used to convert a primitive type to a class |
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Boxing |
converting a primitive to a class |
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Concurrency |
multiple threads running at the same time working with the same resources |
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multithreading |
enables complete use of cpu. when multiple threads run at the same time. |
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thread |
a sequence of programmed instructions |
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process |
an instance of a program. has memory and atleast one thread |