How to Sort a Java Array of Objects by Multiple Fields (Name then Age)?

Sorting by Multiple Fields in Java

Sorting data is a common task in Java, especially when working with complex objects. When sorting by multiple fields, the order of operations becomes crucial. Let's consider a scenario:

Challenge:

Given an array of Person objects with attributes age and name, how can you sort this array alphabetically by name and then by age? What algorithm would be suitable for this task?

Solution:

To sort a collection of objects by multiple fields, Java provides Collections.sort. This can be achieved using a Comparator to define the sorting logic. Here's how you can implement it:

This sorting algorithm first compares the names of the objects. If the names are equal, it proceeds to compare their ages. The compareTo method is used for both string and integer comparisons.

Algorithm:

The algorithm used here is a hybrid of merge sort and quicksort. Collections.sort utilizes a variant of Timsort, which is an efficient hybrid sorting algorithm that takes advantage of the fact that the array is partially sorted by name.

Result:

Upon executing the order method, the provided list of Person objects will be sorted alphabetically by name and then by age.

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