. Implement in JAVA a method in class binary tree of integer to copy the tree in post-order into a singly linked list 2 Implement in JAVA a recursive method to check that a binary tree of integer numbers is a heap. Implement a JAVA method by adding attribute parent to each node in a binary tree, starting from an existing binary tree using in-order method, assign a reference to each parent of any node of the tree. Example the parent of the root is equal to null. Implement in IAVAamethod to calculate the sum of all values in a binary tree of integers