class Node { } class Comment extends Node { } class Foo { public <T> void foo(java.util.List<T> t1, java.util.List<T> t2) { } public Object bar() { Node node; java.util.List<Node> children = new java.util.LinkedList<Node>(); java.util.List<Comment> commentsToAttribute; foo(children, commentsToAttribute); return children.addAll(commentsToAttribute); } }