java - How do I get the `.class` attribute from a generic type parameter? -

the accepted answer this question describes how create instance of t in generic<t> class. involves passing in class<t> parameter generic constructor , callin newinstance method that.

a new instance of generic<bar> created, , parameter bar.class passed in.

what do if generic type parameter new generic class not known class bar generic type parameter? suppose had other class skeet<j> , wanted create new instance of generic<j> inside class. then, if try pass in j.class following compiler error:

cannot select type variable. 

is there way around this?

the specific bit of code triggering error me is:

public class inputfield<w extends component & widgetinterface>                                                  extends inputfieldarray<w> {   public inputfield(string labeltext)   {     super(new string[] {labeltext}, w.class);   }   /* ... */ }  public class inputfieldarray<w extends component & widgetinterface>                                                                  extends jpanel {    /* ... */   public inputfieldarray(string[] labeltext, class<w> clazz)                           throws instantiationexception, illegalaccessexception   {     /* ... */      (int = 0 ; < labeltext.length ; i++) {       newlabel = new jlabel(labeltext[i]);       newwidget = clazz.newinstance();       /* ... */     }     /* ... */   }   /* ... */ } 

the error happens, because can't write w.class. there other way of passing in same information?

using .class on type parameter isn't allowed - because of type erasure, w have been erased component @ runtime. inputfield need take class<w> caller, inputfieldarray:

public inputfield(string labeltext, class<w> clazz) {     super(new string[] {labeltext}, clazz); }