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Generics

 
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Hi,

I came across a question in the Whizzlab test, whose answer I have found confusing.

According to it this code would compile but with warnings:

public static void main(String[] args) {

List<? extends Object> ll = new LinkedList<? extends Object>();
ll.add("String");
ll.add(4);
ll.add(true);
ll.toString();

}


but this one would compile without warnings:

public static void main(String[] args) {

List<Object> ll = new LinkedList<Object>();
ll.add("String");
ll.add(4);
ll.add(true);
ll.toString();

}


My understanding is that:

List<Object> ll = new LinkedList<Object>();
mean the same thing as

List<? extends Object> ll = new LinkedList<? extends Object>();
but not according to Whizzlab

Could anyone clarify please?

Thank you
Katrin
 
Katrin Perry
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Sorry, the second code extract would cause compile error according to Whizzlab.
 
Java Cowboy
Posts: 16084
88
Android Scala IntelliJ IDE Spring Java
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Note: You can use code tags to make the forum format your code nicely.
 
Katrin Perry
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Thanks for the suggestion, but this can't be a reason not to answer my question.
 
Jesper de Jong
Java Cowboy
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Continued here.
 
Consider Paul's rocket mass heater.
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