To update an object in an array of objects in Java, you can use the following steps:

1. Find the index of the object in the array that you want to update. You can do this using a loop or the java.util.Arrays.binarySearch() method.

2. Once you have the index of the object, you can use the array[index] syntax to access the object and update its properties.

Here is an example of how you can update an object in an array of objects in Java:

// Define the array of objects
Person[] people = {new Person("Alice", 25), new Person("Bob", 30), new Person("Charlie", 35)};

// Find the index of the object that you want to update
int index = -1;
for (int i = 0; i < people.length; i++) {
    if (people[i].getName().equals("Bob")) {
        index = i;
        break;
    }
}

// Update the object at the index
if (index != -1) {
    people[index] = new Person("Bob", 40);
}

In this example, the Person class has a name and age property, and the getName() and getAge() methods are used to access these properties. The code loops through the array of Person objects and finds the object with the name “Bob”. Once the index is found, the object is updated by creating a new Person object with the same name and a different age.

Note that this approach will only work if the objects in the array are mutable. If the objects are immutable, you will need to create a new object to update the properties.

For more information on arrays in Java, you can refer to the Java documentation: https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/Arrays.html