Form Biggest number

import java.util.*;
public class Main {
static Scanner sc = new Scanner(System.in);
public static void main(String args[]) {
int t = sc.nextInt();
while(t>0){
int n = sc.nextInt();
int[] arr = create(n);
formBiggest(arr, n);
display(arr, n);
t–;
}
}
public static int[] create(int n){
int[] arr = new int[n];
for(int i = 0;i<n;i++){
int a = sc.nextInt();
arr[i] = a;
}
return arr;
}
public static void formBiggest(int[] arr, int n){
for(int i = 0; i<n-1;i++){
for(int j = 0; j<n - i - 1;j++){
String a = String.valueOf(arr[j]);
String b = String.valueOf(arr[j+1]);
String c = a + b;
String d = b + a;
if(Integer.parseInt(d)>Integer.parseInt©){
int temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}
public static void display(int[] arr, int n){
for(int i = 0; i<n;i++){
System.out.print(Integer.toString(arr[i]));
}
}
}

Please find error if any all test cases are not running