[java] When should we use Observer and Observable?

I have written a short description of the observer pattern here: http://www.devcodenote.com/2015/04/design-patterns-observer-pattern.html

A snippet from the post:

Observer Pattern : It essentially establishes a one-to-many relationship between objects and has a loosely coupled design between interdependent objects.

TextBook Definition: The Observer Pattern defines a one-to-many dependency between objects so that when one object changes state, all of its dependents are notified and updated automatically.

Consider a feed notification service for example. Subscription models are the best to understand the observer pattern.

Examples related to java

Under what circumstances can I call findViewById with an Options Menu / Action Bar item? How much should a function trust another function How to implement a simple scenario the OO way Two constructors How do I get some variable from another class in Java? this in equals method How to split a string in two and store it in a field How to do perspective fixing? String index out of range: 4 My eclipse won't open, i download the bundle pack it keeps saying error log

Examples related to design-patterns

How to implement a simple scenario the OO way Implementing Singleton with an Enum (in Java) What is difference between MVC, MVP & MVVM design pattern in terms of coding c# Best Practices for mapping one object to another REST API Login Pattern When should we use Observer and Observable? How to implement a FSM - Finite State Machine in Java Function in JavaScript that can be called only once Thread Safe C# Singleton Pattern Repository Pattern Step by Step Explanation

Examples related to observable

Http post and get request in angular 6 Angular 4: InvalidPipeArgument: '[object Object]' for pipe 'AsyncPipe' TypeError: You provided an invalid object where a stream was expected. You can provide an Observable, Promise, Array, or Iterable How can I create an observable with a delay Return an empty Observable Angular/RxJs When should I unsubscribe from `Subscription` Using an array from Observable Object with ngFor and Async Pipe Angular 2 How to get data from observable in angular2 How to catch exception correctly from http.request()? How to create an Observable from static data similar to http one in Angular?

Examples related to observer-pattern

Delegation: EventEmitter or Observable in Angular When should we use Observer and Observable? Determine what attributes were changed in Rails after_save callback? Super-simple example of C# observer/observable with delegates

Examples related to observers

When should we use Observer and Observable?