public static <K, V> HashMap<K, V> newHashMap() {
        return new HashMap<>(16);
    }
Creates a <i>mutable</i>, empty {@code HashMap} instance.

<p><b>Note:</b> if mutability is not required, use ImmutableMap.of() instead.

<p><b>Note:</b> if {@code K} is an {@code enum} type, use newEnumMap instead.

<p><b>Note for Java 7 and later:</b> this method is now unnecessary and should be treated as
deprecated. Instead, use the {@code HashMap} constructor directly, taking advantage of the new
<a href="http://goo.gl/iz2Wi">"diamond" syntax</a>.

@return a new, empty {@code HashMap}
fastexcel-core/src/main/java/cn/idev/excel/util/MapUtils.java