blocks|key|1017797|text|可能是因为你在和unmodifiable+wrapper一起工作。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1017798|更改此行：|1017799|List<String>+list+=+Arrays.asList(split);|code-block|syntax|javascript|1017800|到这一行：|1017801|List<String>+list+=+new+LinkedList<>(Arrays.asList(split));|1017802|entityMap|0|LINK|mutability|MUTABLE|url|http://java.sun.com/j2se/1.5.0/docs/api/java/util/Collections.html#unmodifiableList(java.util.List))^0|8|K|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|6|7|10|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|11|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|12|8|@]|9|@]|C|$]]|$1|M|3|N|5|H|7|13|8|@]|9|@]|C|$I|J]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]]]

Probably because you're working with <a href="http://java.sun.com/j2se/1.5.0/docs/api/java/util/Collections.html#unmodifiableList(java.util.List)" rel="noreferrer">unmodifiable wrapper</a>.

Change this line:

<pre><code>List&lt;String&gt; list = Arrays.asList(split);
</code></pre>

to this line:

<pre><code>List&lt;String&gt; list = new LinkedList&lt;&gt;(Arrays.asList(split));
</code></pre>

blocks|key|1232377|text|Arrays.asList()返回的列表可能是不可变的。你能试一下吗？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1232378|List<String>+list+=+new+ArrayList<>(Arrays.asList(split));|code-block|syntax|javascript|1232379|entityMap^0|0|F|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

The list returned by <code>Arrays.asList()</code> might be immutable. Could you try
<pre><code>List&lt;String&gt; list = new ArrayList&lt;&gt;(Arrays.asList(split));
</code></pre>

blocks|key|1017896|text|当你试图对集合执行一些不允许的操作时，这个UnsupportedOperationException就会出现，在你的例子中，当你调用Arrays.asList时，它不会返回一个java.util.ArrayList。它返回一个java.util.Arrays$ArrayList，这是一个不可变的列表。您不能向其中添加内容，也不能从中删除内容。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1017897|entityMap^0|1U|D|2G|J|35|Q|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|O|8|@]|D|@]|E|$]]]|G|$]]

This UnsupportedOperationException comes when you try to perform some operation on collection where its not allowed and in your case, When you call <code>Arrays.asList</code> it does not return a <code>java.util.ArrayList</code>. It returns a <code>java.util.Arrays$ArrayList</code> which is an immutable list. You cannot add to it and you cannot remove from it.

blocks|key|1232499|text|我认为替换：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1232500|List<String>+list+=+Arrays.asList(split);|code-block|syntax|javascript|1232501|使用|1232502|List<String>+list+=+new+ArrayList<String>(Arrays.asList(split));|1232503|解决了问题。|1232504|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I think that replacing:

<pre><code>List&lt;String&gt; list = Arrays.asList(split);
</code></pre>

with

<pre><code>List&lt;String&gt; list = new ArrayList&lt;String&gt;(Arrays.asList(split));
</code></pre>

resolves the problem.

blocks|key|1232522|text|对于这个问题，我有另一个解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1232523|List<String>+list+=+Arrays.asList(split);
List<String>+newList+=+new+ArrayList<>(list);|code-block|syntax|javascript|1232524|在newList上工作;)|offset|length|style|CODE|1232525|entityMap^0|0|0|1|7|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I've got another solution for that problem:

<pre><code>List&lt;String&gt; list = Arrays.asList(split);
List&lt;String&gt; newList = new ArrayList&lt;&gt;(list);
</code></pre>

work on <code>newList</code> ;)

blocks|key|1017978|text|下面是来自数组的代码片段|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1017979|public+static+<T>+List<T>+asList(T...+a)+{
++++++++return+new+ArrayList<>(a);
++++}

++++/**
+++++*+@serial+include
+++++*/
++++private+static+class+ArrayList<E>+extends+AbstractList<E>
++++++++implements+RandomAccess,+java.io.Serializable
++++{
++++++++private+static+final+long+serialVersionUID+=+-2764017481108945198L;
++++++++private+final+E[]+a;|code-block|syntax|javascript|1017980|因此，当调用asList方法时，它会返回自己的私有静态类版本的列表，该列表不会覆盖从AbstractList到数组中存储元素的add函数。所以默认情况下，抽象列表中的add方法会抛出异常。|1017981|所以它不是正则数组列表。|1017982|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Following is snippet of code from Arrays 

<pre><code>public static &lt;T&gt; List&lt;T&gt; asList(T... a) {
 return new ArrayList&lt;&gt;(a);
 }

 /**
 * @serial include
 */
 private static class ArrayList&lt;E&gt; extends AbstractList&lt;E&gt;
 implements RandomAccess, java.io.Serializable
 {
 private static final long serialVersionUID = -2764017481108945198L;
 private final E[] a;
</code></pre>

so what happens is that when asList method is called then it returns list of its own private static class version which does not override add funcion from AbstractList to store element in array. So by default add method in abstract list throws exception.

So it is not regular array list.

blocks|key|1232562|text|替换|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1232563|List<String>+list=Arrays.asList(split);|code-block|syntax|javascript|1232564|至|1232565|List<String>+list+=+New+ArrayList<>();
list.addAll(Arrays.asList(split));|1232566|或|1232567|List<String>+list+=+new+ArrayList<>(Arrays.asList(split));|1232568|1232569|List<String>+list+=+new+ArrayList<String>(Arrays.asList(split));|1232570|或者(更适合于删除元素)|1232571|List<String>+list+=+new+LinkedList<>(Arrays.asList(split));|1232572|entityMap^0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Y|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Z|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|10|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|11|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|O|3|L|5|6|7|13|8|@]|9|@]|A|$]]|$1|P|3|Q|5|D|7|14|8|@]|9|@]|A|$E|F]]|$1|R|3|S|5|6|7|15|8|@]|9|@]|A|$]]|$1|T|3|U|5|D|7|16|8|@]|9|@]|A|$E|F]]|$1|V|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|W|$]]

Replace 

<pre><code>List&lt;String&gt; list=Arrays.asList(split);
</code></pre>

to

<pre><code>List&lt;String&gt; list = New ArrayList&lt;&gt;();
list.addAll(Arrays.asList(split));
</code></pre>

or

<pre><code>List&lt;String&gt; list = new ArrayList&lt;&gt;(Arrays.asList(split));
</code></pre>

or

<pre><code>List&lt;String&gt; list = new ArrayList&lt;String&gt;(Arrays.asList(split));
</code></pre>

or (Better for Remove elements)

<pre><code>List&lt;String&gt; list = new LinkedList&lt;&gt;(Arrays.asList(split));
</code></pre>

blocks|key|1232603|text|Arrays.asList()在内部使用固定大小的数组。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1232604|您不能在此Arrays.asList()中动态添加或删除|1232605|使用这个|1232606|Arraylist<String>+narraylist=new+ArrayList(Arrays.asList());|code-block|syntax|javascript|1232607|在narraylist中，您可以轻松地添加或删除项目。|1232608|entityMap^0|0|F|0|5|F|0|0|0|1|A|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|Y|8|@]|D|@]|E|$]]|$1|J|3|K|5|L|7|Z|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|6|7|10|8|@$9|11|A|12|B|C]]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|R|$]]

<code>Arrays.asList()</code> uses fixed size array internally. 
You can't dynamically add or remove from this<code>Arrays.asList()</code>

Use this 

<pre><code>Arraylist&lt;String&gt; narraylist=new ArrayList(Arrays.asList());
</code></pre>

In <code>narraylist</code> you can easily add or remove items.

blocks|key|1018053|text|Arraylist+narraylist=Arrays.asList()；//返回不可变的arraylist使其成为可变的解决方案为:+Arraylist+narraylist=new+ArrayList(Arrays.asList())；|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1018054|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Arraylist narraylist=Arrays.asList(); // Returns immutable arraylist
To make it mutable solution would be:
Arraylist narraylist=new ArrayList(Arrays.asList());

blocks|key|1018108|text|创建一个新列表并在新列表中填充有效值对我来说很有效。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1018109|代码抛出错误-|1018110|List<String>+list+=+new+ArrayList<>();
+++for+(String+s:+list)+{
+++++if(s+is+null+or+blank)+{
++++++++list.remove(s);
+++++}
+++}
desiredObject.setValue(list);|code-block|syntax|javascript|1018111|修复后-|1018112|+List<String>+list+=+new+ArrayList<>();
+List<String>+newList=+new+ArrayList<>();
+for+(String+s:+list)+{
+++if(s+is+null+or+blank)+{
++++++continue;
+++}
+++newList.add(s);
+}
+desiredObject.setValue(newList);|1018113|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Creating a new list and populating valid values in new list worked for me.

Code throwing error - 

<pre><code>List&lt;String&gt; list = new ArrayList&lt;&gt;();
 for (String s: list) {
 if(s is null or blank) {
 list.remove(s);
 }
 }
desiredObject.setValue(list);
</code></pre>

After fix - 

<pre><code> List&lt;String&gt; list = new ArrayList&lt;&gt;();
 List&lt;String&gt; newList= new ArrayList&lt;&gt;();
 for (String s: list) {
 if(s is null or blank) {
 continue;
 }
 newList.add(s);
 }
 desiredObject.setValue(newList);
</code></pre>

I have this code:

<pre><code>public static String SelectRandomFromTemplate(String template,int count) {
 String[] split = template.split("|");
 List&lt;String&gt; list=Arrays.asList(split);
 Random r = new Random();
 while( list.size() &gt; count ) {
 list.remove(r.nextInt(list.size()));
 }
 return StringUtils.join(list, ", ");
}
</code></pre>

I get this:

<pre><code>06-03 15:05:29.614: ERROR/AndroidRuntime(7737): java.lang.UnsupportedOperationException
06-03 15:05:29.614: ERROR/AndroidRuntime(7737): at java.util.AbstractList.remove(AbstractList.java:645)
</code></pre>

How would be this the correct way? Java.15

Why do I get an UnsupportedOperationException when trying to remove an element from a List?

Java

我有这样的代码：public static String SelectRandomFromTemplate(String template,int count) { String[] split = template.split("|"); List<String> list=Arrays.asList(spl...

问为什么在尝试从列表中删除元素时会出现UnsupportedOperationException？
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问为什么在尝试从列表中删除元素时会出现UnsupportedOperationException？
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