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OBSERVER DESIGN PATTERN IN JAVA WITH REAL WORLD
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OBSERVER DESIGN PATTERN IN JAVA WITH REAL WORLD
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• Java is a fundamental fundamental Java standard
  in which the Observer observes any change in the
  state or ownership of the Subject.
• For example, the company updates all its
  shareholders for any decision they make here. The
  company is object and the shareholders are
  observers, any change in the policy of the
  company and the Company notifies all its
  shareholders or observers.

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OBSERVER DESIGN PATTERN IN JAVA WITH REAL WORLD
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• This was a simple explanation of the real world
  of the Observer pattern. In this article, we will
  detail what is the Observer Design pattern, what
  is the benefit of the observer design pattern,
  example pattern or observer in Java and some
  other points.
• As well as the decorator design pattern and the
  factory pattern in Java, the observer pattern is
  also used in the JDK. Java pattern example of the
  observer design pattern What is the observer
  design pattern? Observer in Java code ExampleThe
  pattern of observer design in Java is a very
  important pattern and, as the name suggests, is
  used to observe things.

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OBSERVER DESIGN PATTERN IN JAVA WITH REAL WORLD
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• Suppose you want to notify the change in a
  particular object that observe this object and
  Changes will be notified to you.
• The object that is being observed is referenced
  as Subject and the classes that observe the
  subject are called Observer.
• This is a beautiful standard and is used
  intensively together with the Model View
  Controller Design standard,

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OBSERVER DESIGN PATTERN IN JAVA WITH REAL WORLD
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• in which the model change is propagated for the
  visualization, so you can render with modified
  information.
• Observer pattern is also a very popular Java
  interview question and mainly asked at the upper
  or upper middle level.
• Problem that is solved by the Observer Pattern
  If we have the requirement that yes a specific
  object change its state and depend on This
  changes some or the group of objects
  automatically change their state,
• we need to implement observer pattern that will
  reduce the coupling between objects.

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OBSERVER DESIGN PATTERN IN JAVA WITH REAL WORLD
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• In the real world, if you try to find an example,
  see when we sign a new phone connection whenever
  the customer registers with this company,
• all other departments are notified and,
• depending on the status of the verification,
  verification of the address is check, then send
  the welcome kit, etc.

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OBSERVER DESIGN PATTERN IN JAVA WITH REAL WORLD
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• As the pattern design pattern is implemented in
  Java For the implementation of this standard,
  the java makes our task very easy,
• the developer does not need to do much to
  implement this pattern.
• In the java.util package, we can find
  interfaces, classes and methods to implement this
  standard.

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OBSERVER DESIGN PATTERN IN JAVA WITH REAL WORLD
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• Public interface service Any class that
  implements this interface must be notified when
  the subject or observable object changes its
  status .
• Update (Ob Observable, Object arg) This method
  is called when the subject is changed. Observable
  class It is a subject to whom the observer wants
  to observe.

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OBSERVER DESIGN PATTERN IN JAVA WITH REAL WORLD
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• The other method Important addObserver
  (Observer or) add observers in the set of
  observers to this object or object
  obserlbel.deleteObserver (Observer o) exclude
  observers in the set of observers.hasChanged ()
  check if the object has changed. clea rChanged
  () this method will indicate that the subject
  has not changed or that all observers have been
  notified when changes are made .notifyObservers
  () notifies all observers if the object has
  changed.
• Design pattern observer Java The main advantage
  is the low coupling between objects called
  observer and observable.

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OBSERVER DESIGN PATTERN IN JAVA WITH REAL WORLD
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• The disadvantage is that, at some point, if any
  problem occurs, debugging becomes very difficult
  because the flow of control is implicitly between
  observers and observables, we can predict that
  now the observer will fire and if there is a
  chain between observers, the debugger it becomes
  more complex.
• Another issue is memory management, since the
  subject will contain all the reference of all the
  observers, if we do not cancel the record of the
  object that can create the memory problem. This
  is all in the Observer Pattern in Java.
• Share your thoughts on how and when you used the
  Observer Pattern in your project and any problems
  you have faced?