Unused Generic causing problem

[John Greenwood]

I have a method in a parent class...

public class Parent {
public void setRecords(java.util.List<Record> recs) {
}
}

... which I choose to override in a subclass:

public class Child extends Parent {
public void setRecords(java.util.List<Record> recs) {
}
}    

So far, so good. Now, I want to introduce a type parameter to the parent, so I change its header to ...

public class Parent<T> {

...and this gives me a compile-time error in the child (method has the same erasure as the parent, but does not over-ride it.)

Why? TIA.

[Garrett Rowe]

OK, I can understand a lot of things about generics, but this one is beyond me. As you stated, this does not compile.

import java.util.List;
 
interface Record{}
 
class RecordSetter<T>
{
   public void setRecords(List<Record> recList){}
}
 
public class SpecialRecordSetter extends RecordSetter
{
  public void setRecords(List<Record> recList){}
}

Even though the type parameter on the specified list seemingly has nothing to do with the type paramter of the class. But something funny is going on because this compiles:

import java.util.List;
 
interface Record{}
 
class RecordSetter<T>
{
   public void setRecords(String recList){}
}
 
public class SpecialRecordSetter extends RecordSetter
{
  public void setRecords(String recList){}
}

and obviously this compiles:

import java.util.List;
 
interface Record{}
 
class RecordSetter<T>
{
   public void setRecords(List<Record> recList){}
}
 
public class SpecialRecordSetter<T> extends RecordSetter<T>
{
  public void setRecords(List<Record> recList){}
}

I have no idea whats going on.
[ May 01, 2008: Message edited by: Garrett Rowe ]

[John Greenwood]

Thanks Garrett.

I submitted this to Sun's bug database, and they finally confirmed it as a new bug, ID 6760983.

[Campbell Ritchie]

Originally posted by John Greenwood:
I submitted this to Sun's bug database.

Nice one!