如何在具有特定索引的哈希表中创建链表？

public boolean isCollide(String key, String value){
    int index = key.hashCode();
    if (this.key_array[index]==null) return false;
    else return true;
}
public void addValue(String key, String value){
      Hashtable hashtable = new Hashtable(key,value);
      int index = key.hashCode();
      if (isCollide(key,value)) {
          hashtable.key_array[index]=key;
          hashtable.value_array[index]=value;
      }
      else{
          LinkedList<String> linkedList = new LinkedList<>();
          linkedList.add(value); //how to create a linkedlist on a hashtable?
      }
}
public boolean isCollide(String key, String val