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

Question

I have this code:

public static String SelectRandomFromTemplate(String template,int count) {
   String[] split = template.split(\"|\");
   List         


        

Answer 1

Following is snippet of code from Arrays

public static  List asList(T... a) {
        return new ArrayList<>(a);
    }

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

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.