question about interfaces and generics in Java: type mismatch error -

Let's say I have the following interface:

  Public Interface interface < T increases the number & gt; {Html} 
 
 public vector & lt; Interface & lt; T & gt; & Gt; GetVector (); }   
 and the following classes implementing that interface:  
  Public abstract class C < T's extension number & gt; Applicable interface & lt; T & gt; {Private vector & lt; C & lt; T & gt; & Gt; Vector; Public vector & lt; Interface & lt; T & gt; & Gt; GetVector () {// Error returned this.vector;   
 Legally a  vector & lt; C & lt; T & gt; & Gt;  Why is not legal to return (clearly) a  vector & lt; Interface & lt; Returning T & gt; & Gt; .  C  is actually implementing the  interface , so it should be possible, right? What am I missing?  
 EDIT:  
 Why does this work for non-generic interface? Is this really a common problem?  
  Public Interface Interface {public interface getVector (); } Public abstract class C applied interface {Private C; Public interface getVector () {// errror return this.c; }}    
 
 
 Because  vector  is clearly created < Code> Interface & lt; T & gt; ,  Interface & lt; T & gt; Not the things to expand, I believe that if you defined the definition of  
  public vector & lt; Extends the interface & lt; T & gt; & Gt; GetVector ();   
 The problem is that for some  V, T  or  V extends T  that  foo < V>   Foo & lt; T & gt;  does not have an overflow. The compiler does not test legacy on general arguments unless you explicitly point to that extension point.  
  vector & lt;? Using the  Interface & lt; T & gt; , while  vector & lt; Interface & lt; T & gt; & Gt;  This means that the interface to apply or extend any class is & lt; T & gt;  means "vector with only  interface   items.  
 It is probably more convincing to consider that the  
  Update :  
     
 I tested this and have been compiled without the following errors or warnings  
  Interface interface  gt; public vector & lt;? Extension of the interface & lt; T & gt; getVector () Gt; get.wector () come here this return.vector;}} table C  / code>