Edit or update array with the element and not index

How do you edit an integer in an array by using the element and not the index of the array?
I have this code it asks for the index that I want to edit or change.

Lets say I have this array int[] array = {12, 4, 5, 2, 5};
I want to edit number 12 into 3, so I input in element is 12 and toUpdate 3, How to?

int items;
int element;
System.out.print("Enter the element you want to edit :");
element=sc.nextInt();

for(int J=arr1.length-1 ; J>element; J--) {
      arr1[J] = arr1[J-1];                         
      System.out.print("Enter the you number want to update: ");
      toUpdate=sc.nextInt();
      arr1[element]=toUpdate;
      System.out.println("Update successful..."); 
   }

You could use either a for loop, or the new Java 8 stream library to iterate the array and change the value according to the user input.

import java.util.*;

public class Main {
    public static void main(String[] args) {
        int[] array = {12, 4, 5, 2, 5};

        Scanner sc = new Scanner(System.in);
        System.out.print("Enter the element you want to edit : ");
        int element = sc.nextInt();
        System.out.print("Enter the you number want to update: ");
        int toUpdate = sc.nextInt();

        // Iterate the array using a for loop.
        for(int i = 0; i < array.length; i++) {
            array[i] = (array[i] == element) ? toUpdate : array[i];
        }
        
        System.out.println(Arrays.toString(array));
    }
}

Alternatively you could use a stream instead of the traditional for-loop:
The map call changes all occurrences of element to toUpdate.

array = Arrays.stream(array).map(i -> i == element ? toUpdate : i).toArray();

Or even Arrays.setAll() method:

Arrays.setAll(array, i -> array[i] == element ? toUpdate : array[i]);

Output:

Enter the element you want to edit : 12
Enter the you number want to update: 3
[3, 1, 2, 3, 4]

You can iterate through the array again and check if the element to be updated is present, if it is update it.

for (int i = 0; i < arr.length; i++){
    if (arr[i] == toUpdate){
        arr[i] = newUpdateValue;
        break;
    }
}

P.S: This will update only the first value it comes across.

To update it, you should iterate over all values in arr and replase prvVal with newVal:

public static void update(int[] arr, int prvVal, int newVal) {
    for (int i = 0; i < arr.length; i++)
        if (arr[i] == prvVal)
            arr[i] = newVal;
}