/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
    public List<Class<? extends CommandExecutor>> commandExecutos =
	    new ArrayList<Class<? extends CommandExecutor>>();
		    
	public static void main (String[] args) throws java.lang.Exception
	{
	}
}

interface CommandExecutor { }

class Foo implements CommandExecutor { }
class Bar implements CommandExecutor { }