Write recursive function using java:

A Full Binary Tree (every internal node has two children) is used to represent an arithmetic expression using only operators times and add, as illustrated below represents ((3*5) *4) + (2* (16 + 5)) Nodes in this structure have the following class variables: boolean internalNode;//true for internal nodes, false for leaf nodes int leafValue;//valid for leaf nodes ignored for internal nodes Char operator;//for internal nodes, {'+' '*'}, ignored for leaf nodes Node left Child; Node right Child; Write a recursive function, int eval (Node x), that is passed a (possibly null) reference to the root node of an arithmetic expression tree, as described above, and returns the integer result of evaluating the expression