不能将 java.lang. ClassCastException: java.util.ArrayList $ArrayList 强制转换为 java.util.ArrayList

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.

If you change the type of sos1Value to List, you won't need this cast.

If you must have an instance of java.util.ArrayList, you can create it yourself :

sos1Value = new ArrayList (Arrays.asList(sos1.getValue()));

The ArrayList returned by Arrays.asList() method is NOT java.util.ArrayList it is a static inner class inside Arrays class. So, you can't cast it to java.util.ArrayList.

Try converting / assigning it to a List.

Arrays.asList returns a List implementation, 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.

If you need a java.util.ArrayList, you can just create a copy:

ArrayList<Foo> list = new ArrayList<>(Arrays.asList(sos1.getValue());

If you don't need an ArrayList just remove the cast:

List<Foo> list = Arrays.asList(sos1.getValue());

(if you don't need any members exposed just by ArrayList).

java.lang.ClassCastException: java.util.Arrays$ArrayList cannot be cast to java.util.ArrayList

You need to set the type to java.util.List

The easy way (not efficient) is

ArrayList sos2Value = new ArrayList()
sos2Value.addAll(Arrays.asList(sos1.getValue()))

sos2Value is java.util.ArrayList.
Arrays.asList(sos1.getValue()) is java.util.Arrays$ArrayList

But I'm not clear what you want to do.

I used it in this way:

 private fun getArtists(): ArrayList<ArtistItem> {
var xp = myDb.daoNote().getArtists() as ArrayList<ArtistItem>
val x: List<ArtistItem> =  xp.sortedWith(compareBy { it.isBookmarked})
var pp = ArrayList<ArtistItem>()
for(obj in x)
{
pp.add(obj)
}


return pp
}