code: public String getSuperName() {
          int n = items[readUnsignedShort(header + 4)];
          return n == 0 ? null : readUTF8(n, new char[maxStringLength]);
      }
docs: Returns the internal of name of the super class (see
  {@link Type#getInternalName() getInternalName}). For interfaces, the
  super class is {@link Object}.
  
  @return the internal name of super class, or <tt>null</tt> for
  {@link Object} class.
  
  @see ClassVisitor#visit(int, int, String, String, String, String[])