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java Programming Glossary: mylist.addAssigning a generic List to a concrete ArrayList is causing a compile-time error http://stackoverflow.com/questions/20037561/assigning-a-generic-list-to-a-concrete-arraylist-is-causing-a-compile-time-error is this. Suppose I have a variable myList and I write myList.add new StringWriter What type could myList be It clearly can't.. . Therefore any ArrayList Writer would work OK in the line myList.add new StringWriter but any ArrayList PrintWriter would not . Therefore.. to write this ArrayList Writer myList new ArrayList Writer myList.add new StringWriter and yet the compiler should somehow prevent..
Generics : List<? extends Animal> is same as List<Animal>? http://stackoverflow.com/questions/2575363/generics-list-extends-animal-is-same-as-listanimal the following example void mySub List Animal myList myList.add new Cat If you were allowed to pass a List Dog to this function.. will happen void mySub List extends Animal myList myList.add new Cat compile error here Animal a myList.get 0 works fine.. the other way around. void mySub List super Animal myList myList.add new Cat works fine Animal a myList.get 0 compile error here..
Prevent duplicate entries in arraylist http://stackoverflow.com/questions/9962082/prevent-duplicate-entries-in-arraylist new thing Star Wars 3 thing second new thing Star Wars 1 myList.add first myList.add second I would like to include some sort of.. Wars 3 thing second new thing Star Wars 1 myList.add first myList.add second I would like to include some sort of logic so that in..
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