Add null analysis annotation to CollectionUtils

import java.util.ArrayList;

import java.util.Collection;

import javax.annotation.Nonnull;

import javax.annotation.Nullable;

public final class CollectionUtils {

    private CollectionUtils() {

        // This utility class is not publicly instantiable.

    }

    public static <E> ArrayList<E> arrayAsList(final E[] array, final int start, final int end) {

        if (array == null) {

            throw new NullPointerException();

        }

    @Nonnull

    public static <E> ArrayList<E> arrayAsList(@Nonnull final E[] array, final int start,

            final int end) {

        if (start < 0 || start > end || end > array.length) {

            throw new IllegalArgumentException();

        }

     * @param c Collection to test.

     * @return Whether c contains no elements.

     */

    public static boolean isNullOrEmpty(final Collection<?> c) {

    public static boolean isNullOrEmpty(@Nullable final Collection<?> c) {

        return c == null || c.isEmpty();

    }

}

        assertTrue(CollectionUtils.isNullOrEmpty(Collections.EMPTY_SET));

        assertFalse(CollectionUtils.isNullOrEmpty(Collections.singleton("Not empty")));

    }

}