public interface FileFilter{
    boolean accept(File f);
}


public class DirectoryFilter implements FileFilter{
    @Override
    public boolean accept(File f){
        return f.isDirectory();
    }
}

public class Exemple{
    public static void main(String[] args){
        File home = new File(System.getProperty("user.home"));
        File[] liste = home.listFiles(new DirectoryFilter());
        for(File f : liste){
            System.out.println(f);
        }
    }
}