Get generic type of java.util.List

Question

I have;

List stringList = new ArrayList();
List integerList = new ArrayList();

Is

Answer 1

Expanding on Steve K's answer:

/** 
* Performs a forced cast.  
* Returns null if the collection type does not match the items in the list.
* @param data The list to cast.
* @param listType The type of list to cast to.
*/
static  List castListSafe(List data, Class listType){
    List retval = null;
    //This test could be skipped if you trust the callers, but it wouldn't be safe then.
    if(data!=null && !data.isEmpty() && listType.isInstance(data.iterator().next().getClass())) {
        @SuppressWarnings("unchecked")//It's OK, we know List contains the expected type.
        List foo = (List)data;
        return retval;
    }
    return retval;
}
Usage:

protected WhateverClass add(List data) {//For fluant useage
    if(data==null) || data.isEmpty(){
       throw new IllegalArgumentException("add() " + data==null?"null":"empty" 
       + " collection");
    }
    Class colType = data.iterator().next().getClass();//Something
    aMethod(castListSafe(data, colType));
}

aMethod(List foo){
   for(Foo foo: List){
      System.out.println(Foo);
   }
}

aMethod(List bar){
   for(Bar bar: List){
      System.out.println(Bar);
   }
}