public static float[] addAll(float[] array1, float... array2) {
        if (array1 == null) {
            return clone(array2);
        } else if (array2 == null) {
            return clone(array1);
        }
        float[] joinedArray = new float[array1.length + array2.length];
        System.arraycopy(array1, 0, joinedArray, 0, array1.length);
        System.arraycopy(array2, 0, joinedArray, array1.length, array2.length);
        return joinedArray;
    }
<p>Adds all the elements of the given arrays into a new array.</p>
<p>The new array contains all of the element of {@code array1} followed
by all of the elements {@code array2}. When an array is returned, it is always
a new array.</p>

<pre>
ArrayUtils.addAll(array1, null)   = cloned copy of array1
ArrayUtils.addAll(null, array2)   = cloned copy of array2
ArrayUtils.addAll([], [])         = []
</pre>

@param array1  the first array whose elements are added to the new array.
@param array2  the second array whose elements are added to the new array.
@return The new float[] array.
@since 2.1
android/android_framework/base/src/main/java/lang3/ArrayUtils.java