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Table of contents
1.
Introduction
2.
What is Sort String in Java?
3.
Method 1: Arrays.sort() Method
4.
Method 2: Using Java 8 Streams and sorted() Method
5.
Method 3: reverseOrder() Method
6.
Frequently Asked Questions
6.1.
Can I sort strings based on length using these methods?
6.2.
Is it possible to sort an array of strings in case-insensitive order?
6.3.
How can I sort a list of strings in Java 8 using Streams?
7.
Conclusion
Last Updated: Mar 30, 2024
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Sort String in Java

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Introduction

Sorting strings is a fundamental operation in computer science that's essential for organizing & comparing textual data. It's a process where strings are arranged in a certain order, usually alphabetical. 

Sort String in java

In Java, this can be done in various ways, each suitable for different scenarios. We'll explore some common methods, like using the Arrays.sort() method, leveraging Java 8 Streams, & employing the reverseOrder() method. In this article, you'll have a solid understanding of how to sort strings in Java and enhance your programming skills for better data management & analysis.

What is Sort String in Java?

Sorting strings in Java means arranging them in a specific order. This could be alphabetically from A to Z, or even in reverse. Imagine you have a list of your friends' names you want to organize so you can find them easily. Sorting them is like organizing these names in a way that makes sense, like how you'd sort books on a shelf by their titles.

Java, being a versatile language, offers various ways to sort strings. This is handy when working with lots of text data, like names, cities, or even words from a book. It's a bit like tidying up your room: everything goes where it should, making it easier to find what you need later.

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Method 1: Arrays.sort() Method

The Arrays.sort() method is a built-in function in Java that provides an easy way to sort arrays, including arrays of strings. When you use this method on an array of strings, it rearranges the strings in the array into alphabetical order. This is incredibly useful when dealing with lists of words, names, or any set of textual data that needs to be organized.

To use the Arrays.sort() method, you simply call it and pass the array you want to sort as an argument. Here’s how it works in practice:

First, you need an array of strings that you want to sort. For example:

String[] names = {"Zoe", "Adam", "Charles", "Bella"};


In this array, the names are not in any particular order. To sort them alphabetically, you apply the Arrays.sort() method like this:

Arrays.sort(names);


After this line is executed, the array names is modified in place, meaning the original order is changed, and the names are now sorted alphabetically.

To verify the array is sorted, you can print out the contents of the names array like so:

for(String name : names) {
    System.out.println(name);
}


The output will confirm the names are sorted in alphabetical order:

Adam
Bella
Charles
Zoe


Using Arrays.sort() is straightforward and efficient for sorting strings alphabetically in Java. It's a go-to method for quick and easy sorting tasks.

Remember, Arrays.sort() sorts the strings in ascending order by default. If you need them in a different order, there are other methods to explore, which we'll cover next.

Method 2: Using Java 8 Streams and sorted() Method

Java 8 introduced Streams, a powerful feature for processing collections of data in a functional style. One of the operations you can perform with Streams is sorting. When it comes to strings, the sorted() method in the Stream API can sort a collection of strings easily.

Let's look at how you can use Streams and the sorted() method to sort an array of strings. Suppose you have the following array:

String[] names = {"Zoe", "Adam", "Charles", "Bella"};


To sort this array using Streams, you would first convert the array to a Stream, apply the sorted() method, and then collect the results back into an array or a list. Here's how you can do it:

List<String> sortedNames = Arrays.stream(names) // Convert array to Stream
                                 .sorted()       // Sort the Stream
                                 .collect(Collectors.toList()); // Collect results into a List


This code snippet will sort the names array alphabetically, and the sorted names will be stored in the sortedNames list.

To see the result, you can print out the sortedNames list like this:

for(String name : sortedNames) {
    System.out.println(name);
}


The output will be the names sorted in alphabetical order:

Adam
Bella
Charles
Zoe


Using Streams and the sorted() method provides a flexible and powerful way to sort strings. It's especially handy when you're working with collections and you want to perform additional operations, like filtering or mapping, along with sorting.

Method 3: reverseOrder() Method

Sometimes, you might want to sort strings in reverse, like from Z to A. Java makes this easy with the reverseOrder() method, which is part of the Collections class. This method is handy when you need to sort strings in descending order.

Let's use the same array of names as before:

String[] names = {"Zoe", "Adam", "Charles", "Bella"};


To sort these names in reverse order using the reverseOrder() method, you'll need to convert your array to a list first because reverseOrder() works with collections, not arrays directly. Here's how you can do it:

First, convert the array to a list:

List<String> namesList = Arrays.asList(names);


Then, use the Collections.sort() method with Collections.reverseOrder() as the comparator:

Collections.sort(namesList, Collections.reverseOrder());


Now, namesList contains the names sorted in reverse alphabetical order. To display the sorted list, you can use a simple loop:

for(String name : namesList) {
    System.out.println(name);
}


This will output the names in reverse order:

Zoe
Charles
Bella
Adam


The reverseOrder() method is a straightforward way to sort strings in descending order. It's especially useful when you want your data to appear in reverse, like for a countdown or when displaying the most recent items first.

Frequently Asked Questions

Can I sort strings based on length using these methods?

Yes, you can sort strings by length using a custom comparator with the Arrays.sort() or Collections.sort() methods. For example, to sort by length, you can use Arrays.sort(names, Comparator.comparingInt(String::length));.

Is it possible to sort an array of strings in case-insensitive order?

Absolutely. You can achieve case-insensitive sorting by using a custom comparator, such as String.CASE_INSENSITIVE_ORDER, with the Arrays.sort() or Collections.sort() methods.

How can I sort a list of strings in Java 8 using Streams?

To sort a list of strings using Java 8 Streams, you can use the sorted() method of the Stream API, similar to how you sort an array. For a list, it would look like list.stream().sorted().collect(Collectors.toList());.

Conclusion

In this article, we've learned the different methods to sort strings in Java. Starting with the straightforward Arrays.sort() method, we saw how to organize strings in alphabetical order with minimal issues or problems. We then looked into the more flexible approach of using Java 8 Streams and the sorted() method, which is particularly useful for chaining operations on collections. Lastly, we looked at the reverseOrder() method for sorting strings in descending order, showcasing its utility in scenarios where reverse ordering is desired.

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