Method modify

src/java/org/apache/poi/util/BinaryTree.java:1260–1263

increment the modification count -- used to check for concurrent modification of the map through the map and through an Iterator from one of its Set or Collection views

()

     * an Iterator from one of its Set or Collection views
     */
    private void modify()
    {
        _modifications++;
    }

    /**
     * bump up the size and note that the map has changed