java - Generics in Constructor Parameters -

i know silly question since once knew stuff that. have hard time getting done. have constructor class wich should arraylist wich filled objects implement interface called collisionobserver. here constructor-head:

public cursor(gl gl, libraryfinger finger, vector direction, float radius,         int index, arraylist<t extends collisionobserver> observerlist) 

can tell me make big mistake? tried arraylist<collisionobserver> too, doesn't work too, since when call constructor objects implement collisionobserver error message says constructor undifined.

ok, here complete cursor class:

public class cursor implements collisionsubject{  private vector direction; private gl gl; private float radius; private libraryfinger finger; private glut glut; protected static float[] sphere_center = new float[3]; private arraylist<collisionobserver> observer = new arraylist<collisionobserver>();  public cursor(gl gl, libraryfinger finger, vector direction, float radius, int index, arraylist<t extends collisionobserver> observerlist){     this.gl = gl;     this.finger = finger;     this.direction = direction;     this.radius = radius;     glut = new glut();  //finetuning fingermovements! vector delivered leaplistener considered //raw-data. has adjusted environment in fingertracking used.     sphere_center[0] = (float) (finger.getx()/15);     sphere_center[1] = (float) ((finger.gety()/20)*-1);     sphere_center[2] = (float) (finger.getz()/5);      gl.gltranslatef(sphere_center[0], sphere_center[1], sphere_center[2]);     gl.glenable(gl.gl_cull_face);     gl.glcullface(gl.gl_back);     gl.glcolor3f(0.757f, 0.804f, 0.804f);      glut.glutsolidsphere(radius, 16, 16);     (int = 0; < index; i++){         registercollisionobserver(observerlist.get(i));     }     myposition(); }  @override public void registercollisionobserver(collisionobserver o) {     observer.add(o);         }  @override public void removecollisionobserver(collisionobserver o) {     if (!observer.isempty()) {         int = observer.indexof(o);         if (i >= 0)             observer.remove(i);     } }   @override public void myposition() {     (int = 0; < observer.size(); i++) {         collisionobserver o = observer.get(i);         o.collision(finger, direction, radius);     } } 

and here how invoke constructor. in 2 different classes. first class:

private arraylist<picture> piclist = new arraylist<picture>(); 

the type "picture" implements interface collisionobserver

 cursor finger = new cursor(gl, lfl[i], listener.getfl().get(i).direction(), 0.5f, piclist.size(), piclist); 

same thing class two. type shelf implements collisionobserver interface:

    private arraylist<shelf> shelflist = new arraylist<shelf>();     cursor finger = new cursor(gl, lfl[i], listener.getfl().get(i).direction(), 0.5f, shelflist.size(), shelflist); 

in 1 of constructor parameters, have declared:

arraylist<t extends collisionobserver> 

where'd t come from? if want have arraylist contain elements type-bound class, use of t appropriate here.

from seems like, want list of objects implement collisionobserver, declaration want:

arraylist<? extends collisionobserver>