To implement a modifiable collection, the programmer must additionally override this class’s add method (which otherwise throws an UnsupportedOperationException), and the iterator returned by the iterator method must additionally implement its remove method. The programmer should generally provide a void ...
当List较大时,性能可能会受到影响。 方法二:使用Java 8的Stream API Java 8中引入的Stream API提供了一种更简洁的方式来处理集合数据。通过使用Stream的filter和collect方法,可以轻松地实现取差集的功能。 以下是使用Stream API的代码示例: List<Integer> list1 = Arrays.asList(1, 2, 3, 4, 5); List<Integ...
private final E[] a; ArrayList(E[] storage) { if (storage == null) { throw new NullPointerException("storage == null"); } //直接复制 a = storage; } 迭代器 Iterator, ListIterator List 继承了 Collection 的iterator() 方法,可以获取 Iterator,使用它可以进行向后遍历。 在此基础上,List 还...
Exception in thread "main" java.lang.UnsupportedOperationException at java.util.AbstractList.remove(AbstractList.java:161) at java.util.AbstractList$Itr.remove(AbstractList.java:374) at java.util.AbstractCollection.remove(AbstractCollection.java:293) at JavaBase.List.AsListTest.lambda$asListAdd$0(AsLi...
使用Java中的Arrays工具类中的静态方法.asList(...)进行后续操作可能会出现 java.lang.UnsupportedOperationException异常问题 1、问题出现 比如以下例子: public static void main(String[] args) { Str
Typically, we useArrays.asListor the new Java 9List.ofto create aList. However, both methods return a fixed size or immutableList, it means we can’t modify it, else it throwsUnsupportedOperationException. JavaListExample.java packagecom.mkyong;importjava.util.Arrays;importjava.util.List;public...
java.lang.NullPointerException异常是由于在使用Collectors.toList()方法时,流中存在null值导致的。为了避免这个异常的抛出,我们可以在使用Collectors.toList()方法之前,先使用filter方法过滤掉null值。 Java 8的Stream API和Collectors类为我们提供了强大的数据处理和集合收集功能。然而,在使用这些功能时,我们需要注意处理...
UnsupportedOperationException 异常来实现,在例程里省略掉了。 package com.example.learncollection; import java.util.List; public class UseListAppMain { public static void main(String[] args) { List myList = new MyArrayList(); for (int i = 0; i < 10; i++) { ...
attempting an operation on an ineligible element whose completion would not result in the insertion of an ineligible element into the list may throw an exception or it may succeed, at the option of the implementation. Such exceptions are marked as "optional" in the specification for this interfac...
=null) { sb.append(s); } } catch (Exception e) { e.printStackTrace(); } System.out.println(sb.toString()); return sb.toString(); } private static void getJsonValue(String json) { //The authors of all books:获取json中store下book下的所有author值 List<String> authors1 = JsonPath....