Method isBlack

src/java/org/apache/poi/util/BinaryTree.java:610–613

is the specified black red? if the node does not exist, sure, it's black, thank you @param node the node (may be null) in question @param index _KEY or _VALUE

(Node node, int index)

     * @param index _KEY or _VALUE
     */
    private static boolean isBlack(Node node, int index)
    {
        return node == null ? true : node.isBlack(index);
    }

    /**
     * force a node (if it exists) red