return new interface or return new class implemented interface

InterfaceOrClass

 max@antonov :tmp: 19:24:57 [0] $ javap -c Ber
Compiled from "Ber.java"
class Ber {
  Ber();
    Code:
       0: aload_0
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: return

  public java.io.Serializable getObject();
    Code:
       0: new           #2                  // class BerSer
       3: dup
       4: invokespecial #3                  // Method BerSer."<init>":()V
       7: areturn
}
 max@antonov :tmp: 19:25:00 [0] $ javap -c Ser
Compiled from "Ser.java"
class Ser {
  Ser();
    Code:
       0: aload_0
       1: invokespecial #1                  // Method java/lang/Object."<init>":()V
       4: return

  public java.io.Serializable getObject();
    Code:
       0: new           #2                  // class Ser$1
       3: dup
       4: aload_0
       5: invokespecial #3                  // Method Ser$1."<init>":(LSer;)V
       8: areturn
}