java.lang.UnsupportedOperationException android arraylist

Question

i am getting unsupported operation exception when i remove item from list.

new AlertDialog.Builder(getActivity())
                        .setMessage(result.getString("Message"))
                        .setPositiveButton("OK", new DialogInterface.OnClickListener() {

                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                miPaymentModel.remove(index);
                            })
                        .show();

}

stack trace is here

01-11 16:42:37.610: E/AndroidRuntime(25930): FATAL EXCEPTION: main
01-11 16:42:37.610: E/AndroidRuntime(25930): java.lang.UnsupportedOperationException
01-11 16:42:37.610: E/AndroidRuntime(25930):    at java.util.AbstractList.remove(AbstractList.java:638)
01-11 16:42:37.610: E/AndroidRuntime(25930):    at com.paksoft.people.Fragment.MiPaymentFragment$DeleteCardAccount$1.onClick(MiPaymentFragment.java:395)
01-11 16:42:37.610: E/AndroidRuntime(25930):    at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:166)
01-11 16:42:37.610: E/AndroidRuntime(25930):    at android.os.Handler.dispatchMessage(Handler.java:99)
01-11 16:42:37.610: E/AndroidRuntime(25930):    at android.os.Looper.loop(Looper.java:137)
01-11 16:42:37.610: E/AndroidRuntime(25930):    at android.app.ActivityThread.main(ActivityThread.java:4499)
01-11 16:42:37.610: E/AndroidRuntime(25930):    at java.lang.reflect.Method.invokeNative(Native Method)
01-11 16:42:37.610: E/AndroidRuntime(25930):    at java.lang.reflect.Method.invoke(Method.java:511)
01-11 16:42:37.610: E/AndroidRuntime(25930):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:788)
01-11 16:42:37.610: E/AndroidRuntime(25930):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555)
01-11 16:42:37.610: E/AndroidRuntime(25930):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

Abstract list is an adapter with some methods that by default aren't abstract but instead throw UnsupportedOperationException's

/**
 * {@inheritDoc}
 *
 * <p>This implementation always throws an
 * {@code UnsupportedOperationException}.
 *
 * @throws UnsupportedOperationException {@inheritDoc}
 * @throws IndexOutOfBoundsException     {@inheritDoc}
 */
public E remove(int index) {
    throw new UnsupportedOperationException();
}

The culprit are the following lines in the Arrays implementation. It does not return an java.util.ArrayList, this is a local implementation of an Abstract list with a misleading name java.util.Arrays.ArrayList, which also is private. It is exceptionally horrible coding.

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;

    ArrayList(E[] array) {
        a = Objects.requireNonNull(array);
    }

    @Override
    public int size() {
        return a.length;
    }

    @Override
    public Object[] toArray() {
        return a.clone();
    }

    @Override
    @SuppressWarnings("unchecked")
    public <T> T[] toArray(T[] a) {
        int size = size();
        if (a.length < size)
            return Arrays.copyOf(this.a, size,
                                 (Class<? extends T[]>) a.getClass());
        System.arraycopy(this.a, 0, a, 0, size);
        if (a.length > size)
            a[size] = null;
        return a;
    }

    @Override
    public E get(int index) {
        return a[index];
    }

    @Override
    public E set(int index, E element) {
        E oldValue = a[index];
        a[index] = element;
        return oldValue;
    }

    @Override
    public int indexOf(Object o) {
        if (o==null) {
            for (int i=0; i<a.length; i++)
                if (a[i]==null)
                    return i;
        } else {
            for (int i=0; i<a.length; i++)
                if (o.equals(a[i]))
                    return i;
        }
        return -1;
    }

    @Override
    public boolean contains(Object o) {
        return indexOf(o) != -1;
    }

    @Override
    public void forEach(Consumer<? super E> action) {
        Objects.requireNonNull(action);
        for (E e : a) {
            action.accept(e);
        }
    }

    @Override
    public void replaceAll(UnaryOperator<E> operator) {
        Objects.requireNonNull(operator);
        E[] a = this.a;
        for (int i = 0; i < a.length; i++) {
            a[i] = operator.apply(a[i]);
        }
    }

    @Override
    public Spliterator<E> spliterator() {
        return Spliterators.spliterator(a, Spliterator.ORDERED);
    }
}

Answer 2

On Arrays.asList returning a fixed-size list

From the Class API Documentation here :

Arrays.asList: Returns a fixed-size list backed by the specified array.

You can't add to it; you can't remove from it. You can't structurally modify the List.

To support this type of operation

Create a LinkedList, which supports faster remove.

List<String> list = new LinkedList<String>(Arrays.asList(split));

Ref Answer: https://stackoverflow.com/a/2965808/2123594 and credits are goes to @polygenelubricants

Answer 3

Try this..

You cannot remove item from the list returned by Arrays.asList because the list is backed by the original array

List<String> miPaymentModel = new LinkedList<String>(Arrays.asList(array_name));

Reference from

Link 1 and Link 2