the method holdtrack.enqueue(smallestParcel); is Int cannot be dereferenced

public static boolean sequence(){
    int holdtrack=0;

    for(int i=0;i<9;i++)
        while(holdtrack<3){
            if(!track[holdtrack].isEmpty()){
                if(track[holdtrack].front().equals(smallestParcel)){
                    holdtrack.enqueue(smallestParcel);
                    System.out.println("Move parcel " + smallestParcel
                        + " from holding buffer track H" + (holdtrack + 1) + " to output buffer");
                    smallestParcel++;
                    break;
                }
            }
            holdtrack++;
    }
    return true;
}