jetbrick-commons/src/main/java/jetbrick/collections/ListUtils.java
public static <T> T[] asArray(Collection<T> items, Class<T> elementType) {
        if (items == null) {
            return null;
        }
        @SuppressWarnings("unchecked")
        T[] results = (T[]) Array.newInstance(elementType, items.size());
        int i = 0;
        for (T item : items) {
            results[i++] = item;
        }
        return results;
    }
public static <T> T[] asArray(Collection<T> items, Class<T> elementType) {
        if (items == null) {
            return null;
        }
        @SuppressWarnings("unchecked")
        T[] results = (T[]) Array.newInstance(elementType, items.size());
        int i = 0;
        for (T item : items) {
            results[i++] = item;
        }
        return results;
    }
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