Core Java Questions et reponses d'entretien
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Question 211. How are Observer and Observable used?
Objects that subclass the Observable class maintain a list of observers. When an Observable object is updated it invokes the update() method of each of its observers to notify the observers that it has changed state. The Observer interface is implemented by objects that observe Observable objects.
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Question 212. How does Java handle integer overflows and underflows?
It uses those low order bytes of the result that can fit into the size of the type allowed by the operation.
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Question 213. To what value is a variable of the String type automatically initialized?
The default value of an String type is null.
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Question 214. What is the range of the short type?
The range of the short type is -(2^15) to 2^15 - 1.
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Question 215. What is Downcasting ?
Downcasting is the casting from a general to a more specific type, i.e. casting down the hierarchy
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