java - The type parameter T is hiding the type T -

my question is: why, if use linearlayout, instead of object, "result" of asynctask (tablewithinexplisttask<params, progress, linearlayout>) , eclipse give me many errors cannot instantiate type linearlayout?
seems me doesn't recognise linearlayout anymore in createformattedcell() , can't undertstand why.
in asynctask declaration linearlayout has yellow underline , eclipse says: the type parameter linearlayout hiding type linearlayout.
please can explain me?

here code of class:

import android.content.context; import android.graphics.color; import android.graphics.typeface; import android.os.asynctask; import android.view.view; import android.widget.linearlayout; import android.widget.textview;  public class tablewithinexplisttask<params, progress, linearlayout> extends asynctask<params, progress, linearlayout> {      private final int table_border = 1;     private final int table_text_padding = 10;       private context context = null;     private string str = null;     private boolean tableheader = false;     private linearlayout column = null;      public tablewithinexplisttask(context context, string str, boolean tableheader, linearlayout column) {         this.context = context;         this.str = str;         this.tableheader = tableheader;         this.column = column;     }      @override     protected linearlayout doinbackground(params... arg0) {         return this.createformattedcell(this.tableheader, this.str);     }      @override     protected void onpostexecute(linearlayout result) {         this.column.addview(result);     }      private linearlayout createformattedcell(boolean tabheader, string str) {         // layout che circonda le textview necessario per disegnare il bordo         // delle celle         linearlayout container = new linearlayout(this.context);          container.setpadding(table_border, table_border, 0, 0);         container.setbackgroundcolor(color.black);          textview textview = new textview(this.context);          textview.setpadding(table_text_padding, table_text_padding, table_text_padding, table_text_padding);         textview.setbackgroundcolor(color.white);         linearlayout.layoutparams params = new linearlayout.layoutparams(linearlayout.layoutparams.match_parent,                 linearlayout.layoutparams.match_parent);         textview.setlayoutparams(params);          if (tabheader) {             textview.settypeface(typeface.default_bold);             textview.setbackgroundcolor(this.context.getresources().getcolor(r.color.light_grayish_orange));         }         textview.settext(str);         container.addview(textview);          return container;     }   } 

i see other question don't understand behavior in case.

having generic parameters (the stuff in angle brackets) attached name of class telling java want users of class able specify types involved, , you're using names "variable names" types users choose. see, example, map<k,v>, k , v represent types of map's keys , values. when listed linearlayout type parameter, compiler thought using placeholder other class users pick, , didn't know how construct one.

you're wanting concrete class extend class uses generics, know specific types want fill in there, don't put type parameters on own class, on 1 you're using. example, if writing custom map class mapped strings integers, public class mymap implements map<string, integer>.