import java.util.*; class Test<T> { List<Collection<T>> getList () { return new ArrayList<Collection<T>> (); } public void test1 (Test<T> arg) { List<Collection<T>> result = arg.getList (); result.add <error descr="'add(java.util.Collection<T>)' in 'java.util.List' cannot be applied to '(java.util.HashMap<java.lang.Integer,java.lang.Integer>)'">(new HashMap<Integer, Integer> ())</error>; } }