java.lang.ClassCastException: java.util.Arrays$ArrayList 不能转换为 java.util.ArrayList
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java.lang.ClassCastException: java.util.Arrays$ArrayList cannot be cast to java.util.ArrayList
提问by SaintLike
Can you explain me why does this happen and how can I fix it please?
你能解释一下为什么会发生这种情况吗，我该如何解决？
So I'm using Oracle-ADF and I'm using shuttle components. I get the selected values using the sos1.getValue();
所以我在使用 Oracle-ADF 和穿梭组件。我使用sos1.getValue();
The getValue() method returns an object and I'm trying to convert it to an ArrayList so I can work with it later. Therefore I've created the ArrayList sos1Value
getValue() 方法返回一个对象，我正在尝试将其转换为 ArrayList，以便以后可以使用它。因此我创建了ArrayList sos1Value
However, this line of code is going bananas:
然而，这行代码正在疯狂：
sos1Value = (ArrayList) Arrays.asList(sos1.getValue());
And I keep having a java.lang.ClassCastException: java.util.Arrays$ArrayList cannot be cast to java.util.ArrayList
我一直有一个 java.lang.ClassCastException: java.util.Arrays$ArrayList cannot be cast to java.util.ArrayList
I've tryed other ways like: sos1Value = (ArrayList) sos1.getValue();
我尝试过其他方法，例如： sos1Value = (ArrayList) sos1.getValue();
But I keep having the same problem, what can I do?
但是我总是遇到同样的问题，我该怎么办？
采纳答案by Jon Skeet
Arrays.asListreturns a Listimplementation, but it's not a java.util.ArrayList. It happens to have a classname of ArrayList, but that's a nested class within Arrays- a completely different type from java.util.ArrayList.
Arrays.asList返回一个List实现，但它不是一个java.util.ArrayList. 它的类名恰好为ArrayList，但这是一个嵌套类Arrays- 与java.util.ArrayList.
If you needa java.util.ArrayList, you can just create a copy:
如果你需要一个java.util.ArrayList，你可以创建一个副本：
ArrayList<Foo> list = new ArrayList<>(Arrays.asList(sos1.getValue());
or:
或者：
List<Foo> list = new ArrayList<>(Arrays.asList(sos1.getValue()));
(if you don't need any members exposed just by ArrayList).
（如果您不需要任何仅由 公开的成员ArrayList）。
回答by Eran
Arrays.asList(sos1.getValue());produces an instance of a List implementation (java.util.Arrays$ArrayList) that is not java.util.ArrayList. Therefore you can't cast it to java.util.ArrayList.
Arrays.asList(sos1.getValue());生成一个 List 实现 ( java.util.Arrays$ArrayList)的实例，它不是 java.util.ArrayList。因此你不能将它投射到java.util.ArrayList.
If you change the type of sos1Valueto List, you won't need this cast.
如果您将 的类型更改sos1Value为List，则不需要此演员表。
If you must have an instance of java.util.ArrayList, you can create it yourself :
如果你必须有一个 的实例java.util.ArrayList，你可以自己创建它：
sos1Value = new ArrayList (Arrays.asList(sos1.getValue()));
回答by TheLostMind
The ArrayListreturned by Arrays.asList()method is NOT java.util.ArrayListit is a static inner class inside Arraysclass. So, you can't cast it to java.util.ArrayList.
该ArrayList由归国Arrays.asList()方法不是java.util.ArrayList它是一个静态内部类内部Arrays类。所以，你不能把它投射到java.util.ArrayList.
Try converting / assigning it to a List.
尝试将其转换/分配给List.
