Reverse the Vowels in the given String ?

import java.util.*;

public class Main
{
static void revVowel(String a)
{
int n=a.length();
int x=0,y=n-1;
char q[]=a.toCharArray();
while(x<y)
{
while(!(q[x]=='a' || q[x]=='e' || q[x]=='i' || q[x]=='o' || q[x]=='u'))
{
x++;
}
while(!(q[y]=='a' || q[y]=='e' || q[y]=='i' || q[y]=='o' || q[y]=='u'))
{
y--;
}
if(x<y)
{
char t=q[x];
q[x]=q[y];
q[y]=t;
x++;
y--;
}
}
System.out.print(new String(q));
}
public static void main(String[] args)
{
Scanner s=new Scanner(System.in);
String a=s.nextLine();
revVowel(a);
}
}