Podcast
Questions and Answers
The ______ pattern ensures only one instance of a class
The ______ pattern ensures only one instance of a class
Singleton
The ______ principle hides implementation details and shows only necessary information
The ______ principle hides implementation details and shows only necessary information
Encapsulation
The ______ pattern defines a one-to-many dependency between objects
The ______ pattern defines a one-to-many dependency between objects
Observer
Java has ______ data types, including byte, short, int, long, float, double, char, and boolean
Java has ______ data types, including byte, short, int, long, float, double, char, and boolean
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Inheritance allows creating a new ______ based on an existing class
Inheritance allows creating a new ______ based on an existing class
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The ______ pattern provides a way to create objects without specifying the exact class of object
The ______ pattern provides a way to create objects without specifying the exact class of object
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Access modifiers in Java include ______, private, protected, and default (package-private)
Access modifiers in Java include ______, private, protected, and default (package-private)
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In Java, ______ are special methods that initialize objects when created
In Java, ______ are special methods that initialize objects when created
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What is the primary goal of the Singleton pattern, and how is it achieved?
What is the primary goal of the Singleton pattern, and how is it achieved?
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How does the Factory pattern decouple object creation from specific classes?
How does the Factory pattern decouple object creation from specific classes?
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What is the main purpose of the Abstract Factory pattern, and how is it achieved?
What is the main purpose of the Abstract Factory pattern, and how is it achieved?
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How does the Adapter pattern enable incompatible objects to work together?
How does the Adapter pattern enable incompatible objects to work together?
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What is the primary advantage of separating an object's abstraction from its implementation using the Bridge pattern?
What is the primary advantage of separating an object's abstraction from its implementation using the Bridge pattern?
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What is the key benefit of using the Composite pattern to compose objects into tree structures?
What is the key benefit of using the Composite pattern to compose objects into tree structures?
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How does the Observer pattern enable loose coupling and scalability?
How does the Observer pattern enable loose coupling and scalability?
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What is the primary advantage of using the Strategy pattern to define a family of algorithms?
What is the primary advantage of using the Strategy pattern to define a family of algorithms?
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Study Notes
Design Patterns
- Creational Patterns:
- Singleton Pattern: ensures only one instance of a class
- Factory Pattern: provides a way to create objects without specifying the exact class of object
- Abstract Factory Pattern: provides a way to create families of related objects
- Structural Patterns:
- Adapter Pattern: allows two incompatible objects to work together
- Bridge Pattern: separates an object's abstraction from its implementation
- Composite Pattern: allows clients to treat individual objects and compositions of objects uniformly
- Behavioral Patterns:
- Observer Pattern: defines a one-to-many dependency between objects
- Strategy Pattern: defines a family of algorithms, encapsulates each one, and makes them interchangeable
- Template Method Pattern: defines the skeleton of an algorithm, allowing subclasses to customize it
Object-oriented Programming (OOP)
- Principles:
- Encapsulation: hiding implementation details and showing only necessary information
- Abstraction: exposing only necessary information and hiding implementation details
- Inheritance: creating a new class based on an existing class
- Polymorphism: objects of different classes responding to the same method call
- Concepts:
- Classes and Objects: classes define objects, objects have attributes and methods
- Constructors: special methods that initialize objects when created
- Inheritance and Interfaces: single and multiple inheritance, abstract classes and interfaces
- Access Modifiers: public, private, protected, default (package-private)
Java Syntax
- Variables and Data Types:
- Primitive Data Types: byte, short, int, long, float, double, char, boolean
- Reference Data Types: class, interface, array
- Variable Declaration:
type variableName [= value];
- Operators:
- Arithmetic Operators:
+,-,*,/,%, etc. - Comparison Operators:
==,!=,>,<,>=,<= - Logical Operators:
&&,||,!
- Arithmetic Operators:
- Control Flow:
- Conditional Statements:
if,if-else,switch - Loops:
while,for,do-while - Jump Statements:
break,continue,return
- Conditional Statements:
- Methods:
- Method Declaration:
accessModifier returnType methodName(parameters) { body } - Method Overloading: multiple methods with same name but different parameters
- Method Overriding: subclass provides a specific implementation for a method already defined in its superclass
- Method Declaration:
Design Patterns
-
Creational Patterns: ensure objects are created in a specific way
- Singleton Pattern: guarantees a single instance of a class
- Factory Pattern: creates objects without specifying the exact class
- Abstract Factory Pattern: creates families of related objects
-
Structural Patterns: deal with the structure of classes and objects
- Adapter Pattern: makes incompatible objects work together
- Bridge Pattern: separates abstraction from implementation
- Composite Pattern: treats individual objects and compositions uniformly
-
Behavioral Patterns: define interactions between objects
- Observer Pattern: sets up a one-to-many dependency between objects
- Strategy Pattern: allows interchangeable algorithms
- Template Method Pattern: defines a customizable algorithm skeleton
Object-oriented Programming (OOP)
-
Principles:
- Encapsulation: hides implementation details, shows only necessary info
- Abstraction: exposes necessary info, hides implementation details
- Inheritance: creates a new class based on an existing class
- Polymorphism: objects of different classes respond to the same method call
-
Concepts:
- Classes and Objects: classes define objects, which have attributes and methods
- Constructors: special methods that initialize objects when created
- Inheritance and Interfaces: single and multiple inheritance, abstract classes, and interfaces
- Access Modifiers: public, private, protected, default (package-private)
Java Syntax
-
Variables and Data Types:
- Primitive Data Types: byte, short, int, long, float, double, char, boolean
- Reference Data Types: class, interface, array
-
Variable Declaration:
type variableName [= value];
-
Operators:
-
Arithmetic Operators:
+,-,*,/,%, etc. -
Comparison Operators:
==,!=,>,<, etc.
-
Arithmetic Operators:
Creational Design Patterns
- Singleton Pattern ensures a class has only one instance and provides a global point of access to that instance, featuring a private constructor and a public static method to retrieve the instance.
- Thread-safe implementations of Singleton Pattern include synchronized methods and double-checked locking.
- Factory Pattern provides a way to create objects without specifying the exact class of object that will be created, decoupling object creation from specific classes.
- Abstract Factory Pattern provides an interface for creating families of related or dependent objects without specifying their concrete classes, combining multiple factory patterns to return a family of related objects.
Structural Design Patterns
- Adapter Pattern converts the interface of a class into another interface that clients expect, enabling incompatible objects to work together, with object adapter and class adapter implementations.
- Bridge Pattern separates an object's abstraction from its implementation, allowing them to vary independently, and decoupling abstraction from implementation to enable runtime changes to either.
- Composite Pattern composes objects into tree structures to represent part-whole hierarchies, enabling the treatment of individual objects and compositions uniformly through recursive composition.
Behavioral Design Patterns
- Observer Pattern defines a one-to-many dependency between objects, allowing objects to notify each other of changes, and consists of subject, observer, and notification, enabling loose coupling and scalability.
- Strategy Pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable, enabling runtime algorithm changes through context, strategy, and concrete strategies.
- Template Method Pattern provides a way to allow subclasses to override specific steps of an algorithm without changing its structure, enabling customization and code reuse through abstract class, template method, and hooks.
Other Design Patterns
- MVC Pattern separates an application into three interconnected components: model (data and business logic), view (user interface), and controller (handles user input and updates model and view).
- Dependency Injection Pattern provides components with dependencies, rather than hardcoding them, enabling loose coupling and testability through inversion of control.
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Description
Explore various design patterns in software development, including creational, structural, and behavioral patterns. Learn about Singleton, Factory, Adapter, and more.
