To replace elements in an EnumMap in Java, you can use the put() method to set a new value for an existing key. Here's an example:

import java.util.EnumMap;

enum Color {
    RED, GREEN, BLUE;
}

public class Example {
    public static void main(String[] args) {
        EnumMap<Color, Integer> colorMap = new EnumMap<>(Color.class);

        colorMap.put(Color.RED, 1);
        colorMap.put(Color.GREEN, 2);
        colorMap.put(Color.BLUE, 3);

        System.out.println(colorMap);

        colorMap.put(Color.GREEN, 4);

        System.out.println(colorMap);
    }
}

In this example, we first define an enum called Color, which has three values: RED, GREEN, and BLUE. We then create a new EnumMap object that maps Color keys to Integer values. We use the put() method to insert key-value pairs into the EnumMap.

To replace an element in the EnumMap, we call the put() method with the key for the element we want to replace, and the new value we want to set for that key. In this case, we replace the value associated with the GREEN key from 2 to 4.

After replacing the element, we print out the contents of the EnumMap using the toString() method again. This will output the following:

{RED=1, GREEN=2, BLUE=3}
{RED=1, GREEN=4, BLUE=3}

As you can see, the GREEN key-value pair has been updated with the new value of 4.