Graph Valid Tree

/**
Given n nodes labeled from 0 to n - 1 and a list of undirected edges (each edge is a pair of nodes), write a function to check whether these edges make up a valid tree.
For example:
Given n = 5 and edges = [[0, 1], [0, 2], [0, 3], [1, 4]], return true.
Given n = 5 and edges = [[0, 1], [1, 2], [2, 3], [1, 3], [1, 4]], return false.
Hint:
Given n = 5 and edges = [[0, 1], [1, 2], [3, 4]], what should your return? Is this case a valid tree? According to the definition of tree on Wikipedia: “a tree is an undirected graph in which any two vertices are connected by exactly one path. In other words, any connected graph without simple cycles is a tree.” Note: you can assume that no duplicate edges will appear in edges. Since all edges are undirected, [0, 1] is the same as [1, 0] and thus will not appear together in edges.
*/

public class GraphValidTree{
/*
-use the concept of connected components
-if the number of connected components is 1, then it is a tree else not
*/
public static boolean countComponents(int n, int[][] edges) {
if (n <= 1) {
            return true;
        }
        HashMap<Integer, Integer> map = new HashMap<>();
        for (int i = 0; i < n; i++) {
            map.put(i, i);
        }
        for (int[] edge : edges) {
            int fa_x = find(map, edge[0]);
            int fa_y = find(map, edge[1]);
System.out.println(fa_x +"..."+fa_y+"..."+n);
//for the connected nodes if they have different parents, then their parents should be connected so make an entry for them
            if (fa_x != fa_y) {
                map.put(fa_x, fa_y);
n--;
            }
        }
        return n==1;
    }

    static int find(HashMap<Integer, Integer> map, int x) {
        int parent_comp = map.get(x);
        while (parent_comp != map.get(parent_comp)) {
            parent_comp = map.get(parent_comp);
        }
        return parent_comp;
    }
}