Arrange consonants and vowels

//Arrange consonants and vowels

import java.io.*;
import java.util.*;

class Node {
    char data;
    Node next;
    
    public Node(char data){
        this.data = data;
        next = null;
    }
}

class GFG {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int t = sc.nextInt();

		while(t-- > 0) {
		    int n = sc.nextInt();
		    Node head = null, tail = null;
		    
		    char head_c = sc.next().charAt(0);
		    head = new Node(head_c);
		    tail = head;
		    
		    while(n-- > 1) {
		        tail.next = new Node(sc.next().charAt(0));
		        tail = tail.next;
		    }
		    
		    Solution obj = new Solution();
		    show(obj.arrangeCV(head));
		    
		}
	}
	
	public static void po(Object o) {
	    System.out.println(o);
	}
	
	public static void show(Node head) {
        while(head != null) {
            System.out.print(head.data+" ");
            head = head.next;
        }
        System.out.println();
    }
}

Structure of node class is:
class Node {
    char data;
    Node next;
    
    public Node(char data)  {
        this.data = data;
        next = null;
    }
}

Solution {
    public Node arrangeCV(Node head){
        Node vowel = new Node('a'), con = new Node('b');
        Node vowelH = vowel, conH = con;
        
        while(head != null) {
            char temp = head.data;
            
            if(temp == 'a' || temp == 'e' || temp == 'i' || temp == 'o' || temp == 'u') {
                vowel.next = head;
                vowel = vowel.next;
            }
            
            else {
                con.next = head;
                con = con.next;
            }
            
            head = head.next;
        }
        
        con.next = null;
        vowel.next = conH.next;
        
        return vowelH.next;
    }
}