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Geneics Question

 
Ranch Hand
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Hi all



Error is

TreeSetTest.java:3: unexpected type
found : ? extends Person
required: class or interface without bounds
class Person implements Comparable<? extends Person>{

 
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What is the question?
 
Greenhorn
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question mark works when declaring a reference for a variable ,it doesn't work for generic class and method declaration.

hence the above code will give u err.
 
Amirr Rafique
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Originally posted by Amir Rafique:
Hi all



Error is

 
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8.1.5 Superinterfaces:
Each InterfaceType must name an accessible (�6.6) interface type, or a compile-time error occurs. If the TypeName is followed by any type arguments, it must be a correct invocation of the type declaration denoted by TypeName, and none of the type arguments may be wildcard type arguments, or a compile-time error occurs.
 
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It may help to read:
Can I derive from a wildcard parameterized type?
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