Внести изменение в неизменное дерево

public abstract class SongComponent {
    
    public void displaySongComponentInfo() {
        
        throw new UnsupportedOperationException();
        
    }
 
}

public class SongGroup extends SongComponent {              // Жанр, содержащий листья или другие поджанры (Composite)
    
    private ArrayList<SongComponent> songComponents = new ArrayList<SongComponent>();
    
    private String groupName;
    private String groupDescription;
    
    public SongGroup(String groupName, String groupDesc, ArrayList<SongComponent> componentsList) {
        
        this.groupName = groupName;
        this.groupDescription = groupDesc;
        this.songComponents = componentsList;
        
    }
    
    public String getGroupName() { return this.groupName;}
    public String getGroupDescription() { return this.groupDescription;}
    
    
   /* public void displaySongComponentInfo() {
        
        System.out.println("\n" + getGroupName() + " " + 
                getGroupDescription() + "\n");
        
        Iterator songIterator = songComponents.iterator();
        
        while(songIterator.hasNext()) {
            
            SongComponent songInfo = (SongComponent) songIterator.next();
            songInfo.displaySongComponentInfo();
            
        }
        
    }*/
 
}

public class Song extends SongComponent {                         // Лист 
    
    private String songName;
    private String bandName;
    private int releaseYear;
    
    public Song(String songName, String bandName, int releaseYear) {
        
        this.songName = songName;
        this.bandName = bandName;
        this.releaseYear = releaseYear;
        
    }
    
    public String getSongName() { return songName; }
    public String getBandName() { return bandName; }
    public int getReleaseYear() { return releaseYear; }
    
    /*public void displaySongComponentInfo(){
        
        System.out.println(getSongName() + " was recorded by " +
                getBandName() + " in " + getReleaseYear());
        
    }*/
 
}