Sorry, but for now the only sample is the one included with the distribution.
It can be found in the examples subdirectory.

import net.sourceforge.xcool.*;
import java.io.*;


public class Example {
    
    public static void main(String args[]) throws Exception {
        
        String queries[] = { "a/b", "a/b[1,2]", "(a/b[1, 2]/@attr)[1]"};
        
        for (int i = 0; i < queries.length; i++) {
            InputStream is = Example.class.getResourceAsStream("example.xml");
            String query = queries[i];
            System.out.println("Executing query: " + query);
            System.out.println(getQueryResult(is, query));
            System.out.println("-----");
            is.close();
        }
    }
    
    private static ResultNode getQueryResult(InputStream inputStream, String query)
            throws Exception {
        return Engine.executeQuery(inputStream, query);
    }
}