casting Arrays.asList causing exception: java.util.Arrays$ArrayList cannot be cast to java.util.ArrayList

Question

I\'m new to Java and am trying to understand why the first code snippet doesn\'t cause this exception but the second one does. Since a string array is passed into Arrays.as

Answer 1

If you do this, you won't get any CCE:

ArrayList> stuff = new ArrayList>();
String[] titles = {"ticker", "grade", "score"};
stuff.add(new ArrayList(Arrays.asList(titles)));

As the error clearly states, the class java.util.ArrayList isn't the same as nested static class java.util.Arrays.ArrayList. Hence the exception. We overcome this by wrapping the returned list using a java.util.ArrayList.