Practical usage of wildcard generics in Java -

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Recently there was an examination on Java, and there was a wide section about wildcard genetics in Java. However, little has been said about their use in practice. When should we use them? See a general use: 

  check for zero (archive & lt;? Extension in animal list) {// something}   
 What the documentation says is, it does not allow adding any element to the archive list. So originally a collection of wildcards can be done for read-only. Is this their use only? Is there any practical need for this? For the past four years I have participated in many programming projects in Java, but I have not seen any project that will use such a facility as a wildcard.  
 So, from a practical perspective, is there a situation when wildcard generics are inevitable and necessary?  
  
 
 
 
 So, it is practical to see, is there a situation where the wildcard generics Are indispensable and necessary?   
 I do not think that they are 'indispensable and necessary' because the Java compiler removes them in any way. However, while using them, you get the benefit of a strict type of investigation during compile-time and you avoid type casting. Which way do you want to cast? :)

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