Trie SPOJ Problem - PhoneList TLE
Instead of children = new Node[11], I would use a Map&lt;Integer, Node&gt;.  I'm not sure how you came up with 11.
Sorting is quite expensive.  Maybe you can solve it with a trie alone without sorting, or with sorting alone without a trie.
Small detail: you have random gaps of 2, 3 or 4 empty lines all over the place.




EDIT:
So, instead of arguing, here is my implementation, without sorting and without a terminal value:

    public static class Node&lt;T&gt; {
        private T value;
        private Map&lt;T, Node&lt;T&gt;&gt; children = new HashMap&lt;&gt;();

        public Node(T value) {
            this.value = value;
        }

        public Node&lt;T&gt; getChild(T t) {
            return children.get(t);
        }

        public boolean hasChildren() {
            return !children.isEmpty();
        }

        public void addChild(T t, Node&lt;T&gt; child) {
            children.put(t, child);
        }
    }

    public static boolean hasConflictingPrefixes(String[] numbers) {
        Node&lt;Byte&gt; trie = new Node&lt;&gt;(null);
        for (String number : numbers) {
            Node&lt;Byte&gt; currentNode = trie;
            for (Byte byt : number.getBytes(Charset.forName("UTF-8"))) {
                Node&lt;Byte&gt; childNode = currentNode.getChild(byt);
                if (childNode == null) {
                    childNode = new Node(byt);
                    currentNode.addChild(byt, childNode);
                } else {
                    // current number is longer (or equal) to existing word
                    if (!childNode.hasChildren()) 
                        return true;
                }
                currentNode = childNode;
            }
            // current number is a prefix to another one
            if (currentNode.hasChildren())  
                return true;
        } 
        return false;
    }


I'm not necessarily proud of this code, but it solves this problem.

Note that duplicate numbers are considered as conflicting prefixes, ie. {"911", "911"} has a conflict just as {"911", "9112"}.