Generics duvida codigo nao compila

import java.util.ArrayList;
import java.util.List;
class Pre{
	
	public static void main(String a[]){
		List<Integer> it = new ArrayList<Integer>();
			it.add(88);
			it.add(9);
			PreR r = new PreR();
			
		System.out.println(r.cha(it));
	
	}
}
class PreR{
	public List<Integer> cha(ArrayList<Integer>a){
	return a;}
}

D:\JAVA\SCJP\revisaoka\cap7\Genericos>javac Pre.java

Pre.java:11: cha(java.util.ArrayList<java.lang.Integer>) in PreR cannot be appli

ed to (java.util.List<java.lang.Integer>)

System.out.println(r.cha(it));

^

1 error