public E getFirst() {
        if (mHead == mTail) {
            throw new ArrayIndexOutOfBoundsException();
        }
        return mElements[mHead];
    }
Get first element of the CircularArray.

@return The first element.
@throws {@link ArrayIndexOutOfBoundsException} if CircularArray is empty.
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/util/collection/CircularArray.java