Hi I'm very new to Java and have this problem with building a nested Iterator class for a Doubly Linked List. I'm getting this error on E next method when running the test program. The goal of the next method in the Iterator is to return the next item in the Doubly Linked List.
嗨,我对Java很新,并且在为双向链接列表构建嵌套的Iterator类时遇到了这个问题。运行测试程序时,我在E next方法上遇到此错误。迭代器中下一个方法的目标是返回双链接列表中的下一个项目。
Can anyone advice a fix on my code? Any help is greatly appreciated!
谁能建议修复我的代码?任何帮助是极大的赞赏!
Error message:
Exception in thread "main" java.lang.NullPointerException at dlinkedlist.Deque$DoubleListIterator.next(Deque.java:51)
dlinkedlist.Deque中的线程“main”java.lang.NullPointerException中的异常$ DoubleListIterator.next(Deque.java:51)
public E next() {
if (!hasNext()) throw new NoSuchElementException();
last = current;
E value = current.item;
current = current.next;
index++;
return value;
}
public void remove() { throw new UnsupportedOperationException(); }
}// end class ListIterator
1 个解决方案
#1
It seems your current
object is null. Can you check it?
看来你当前的对象是null。你能检查一下吗?
#1
It seems your current
object is null. Can you check it?
看来你当前的对象是null。你能检查一下吗?