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Once the early-adopter seats are all used, the price will go up and stay at $33/year.

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Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Partner – Microsoft – NPI EA (cat= Spring Boot)
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Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, you can get started over on the documentation page.

And, you can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Partner – Orkes – NPI EA (cat=Spring)
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Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

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With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

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Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

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With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

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Since its introduction in Java 8, the Stream API has become a staple of Java development. The basic operations like iterating, filtering, mapping sequences of elements are deceptively simple to use.

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1. Overview

The Apache Commons Lang 3 library provides support for manipulation of core classes of the Java APIs. This support includes methods for handling strings, numbers, dates, concurrency, object reflection and more.

In addition to providing a general introduction to the library, this tutorial demonstrates methods of the StringUtils class which is used for manipulation of String instances.

2. Maven Dependency

In order to use the Commons Lang 3 library, just pull it from the central Maven repository using the following dependency:

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.14.0</version>
</dependency>

You can find the latest version of this library here.

3. StringUtils

The StringUtils class provides methods for null-safe operations on strings.

Many methods of this class have corresponding ones defined in class java.lang.String, which are not null-safe. However, this section will instead focus on several methods that do not have equivalents in the String class.

4. The containsAny Method

The containsAny method checks if a given String contains any character in the given set of characters. This set of characters can be passed in the form of a String or char varargs.

The following code fragment demonstrates the use of two overloaded flavors of this method with result verification:

String string = "baeldung.com";
boolean contained1 = StringUtils.containsAny(string, 'a', 'b', 'c');
boolean contained2 = StringUtils.containsAny(string, 'x', 'y', 'z');
boolean contained3 = StringUtils.containsAny(string, "abc");
boolean contained4 = StringUtils.containsAny(string, "xyz");
 
assertTrue(contained1);
assertFalse(contained2);
assertTrue(contained3);
assertFalse(contained4);

5. The containsIgnoreCase Method

The containsIgnoreCase method checks if a given String contains another String in a case insensitive manner.

The following code fragment verifies that the String “baeldung.com” comprises “BAELDUNG” when upper and lower case is ignored:

String string = "baeldung.com";
boolean contained = StringUtils.containsIgnoreCase(string, "BAELDUNG");
 
assertTrue(contained);

6. The countMatches Method

The counterMatches method counts how many times a character or substring appears in a given String.

The following is a demonstration of this method, confirming that ‘w’ appears four times and “com” does twice in the String “welcome to www.baeldung.com”:

String string = "welcome to www.baeldung.com";
int charNum = StringUtils.countMatches(string, 'w');
int stringNum = StringUtils.countMatches(string, "com");
 
assertEquals(4, charNum);
assertEquals(2, stringNum);

7. Appending and Prepending Method

The appendIfMissing and appendIfMissingIgnoreCase methods append a suffix to the end of a given String if it does not already end with any of the passed-in suffixes in a case sensitive and insensitive manner respectively.

Similarly, the prependIfMissing and prependIfMissingIgnoreCase methods prepend a prefix to the beginning of a given String if it does not start with any of the passed-in prefixes.

In the following example, the appendIfMissing and prependIfMissing methods are used to add a suffix and prefix to the String “baeldung.com” without these affixes being repeated:

String string = "baeldung.com";
String stringWithSuffix = StringUtils.appendIfMissing(string, ".com");
String stringWithPrefix = StringUtils.prependIfMissing(string, "www.");
 
assertEquals("baeldung.com", stringWithSuffix);
assertEquals("www.baeldung.com", stringWithPrefix);

8. Case Changing Method

The String class already defines methods to convert all characters of a String to uppercase or lowercase. This subsection only illustrates the use of methods changing the case of a String in other ways, including swapCase, capitalize and uncapitalize.

The swapCase method swaps the case of a String, changing uppercase to lowercase and lowercase to uppercase:

String originalString = "baeldung.COM";
String swappedString = StringUtils.swapCase(originalString);
 
assertEquals("BAELDUNG.com", swappedString);

The capitalize method converts the first character of a given String to uppercase, leaving all remaining characters unchanged:

String originalString = "baeldung";
String capitalizedString = StringUtils.capitalize(originalString);
 
assertEquals("Baeldung", capitalizedString);

The uncapitalize method converts the first character of the given String to lowercase, leaving all remaining characters unchanged:

String originalString = "Baeldung";
String uncapitalizedString = StringUtils.uncapitalize(originalString);
 
assertEquals("baeldung", uncapitalizedString);

9. Reversing Method

The StringUtils class defines two methods for reversing strings: reverse and reverseDelimited. The reverse method rearranges all characters of a String in the opposite order, while the reverseDelimited method reorders groups of characters, separated by a specified delimiter.

The following code fragment reverses the string “baeldung” and validates the outcome:

String originalString = "baeldung";
String reversedString = StringUtils.reverse(originalString);
 
assertEquals("gnudleab", reversedString);

With the reverseDelimited method, characters are reversed in groups instead of individually:

String originalString = "www.baeldung.com";
String reversedString = StringUtils.reverseDelimited(originalString, '.');
 
assertEquals("com.baeldung.www", reversedString);

10. The rotate() Method

The rotate() method circularly shifts characters of a String a number of positions. The code fragment below moves all characters of the String “baeldung” four positions to the right and verifies the result:

String originalString = "baeldung";
String rotatedString = StringUtils.rotate(originalString, 4);
 
assertEquals("dungbael", rotatedString);

11. The difference Method

The difference method compares two strings, returning the remainder of the second String, starting from the position where it is different from the first. The following code fragment compares two Strings: “Baeldung Tutorials” and “Baeldung Courses” in both directions and validates the outcome:

String tutorials = "Baeldung Tutorials";
String courses = "Baeldung Courses";
String diff1 = StringUtils.difference(tutorials, courses);
String diff2 = StringUtils.difference(courses, tutorials);
 
assertEquals("Courses", diff1);
assertEquals("Tutorials", diff2);

12. Conclusion

This tutorial introduces String processing in the Apache Commons Lang 3 and goes over the main APIs we can use out of the StringUtils library class.

The code backing this article is available on GitHub. Once you're logged in as a Baeldung Pro Member, start learning and coding on the project.
Baeldung Pro – NPI EA (cat = Baeldung)
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Baeldung Pro comes with both absolutely No-Ads as well as finally with Dark Mode, for a clean learning experience:

>> Explore a clean Baeldung

Once the early-adopter seats are all used, the price will go up and stay at $33/year.

Partner – Microsoft – NPI EA (cat = Spring Boot)
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Azure Container Apps is a fully managed serverless container service that enables you to build and deploy modern, cloud-native Java applications and microservices at scale. It offers a simplified developer experience while providing the flexibility and portability of containers.

Of course, Azure Container Apps has really solid support for our ecosystem, from a number of build options, managed Java components, native metrics, dynamic logger, and quite a bit more.

To learn more about Java features on Azure Container Apps, visit the documentation page.

You can also ask questions and leave feedback on the Azure Container Apps GitHub page.

Partner – Orkes – NPI EA (cat = Spring)
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Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

Try a 14-Day Free Trial of Orkes Conductor today.

Partner – Orkes – NPI EA (tag = Microservices)
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Modern software architecture is often broken. Slow delivery leads to missed opportunities, innovation is stalled due to architectural complexities, and engineering resources are exceedingly expensive.

Orkes is the leading workflow orchestration platform built to enable teams to transform the way they develop, connect, and deploy applications, microservices, AI agents, and more.

With Orkes Conductor managed through Orkes Cloud, developers can focus on building mission critical applications without worrying about infrastructure maintenance to meet goals and, simply put, taking new products live faster and reducing total cost of ownership.

Try a 14-Day Free Trial of Orkes Conductor today.

eBook – HTTP Client – NPI EA (cat=HTTP Client-Side)
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The Apache HTTP Client is a very robust library, suitable for both simple and advanced use cases when testing HTTP endpoints. Check out our guide covering basic request and response handling, as well as security, cookies, timeouts, and more:

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eBook – Java Concurrency – NPI EA (cat=Java Concurrency)
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Handling concurrency in an application can be a tricky process with many potential pitfalls. A solid grasp of the fundamentals will go a long way to help minimize these issues.

Get started with understanding multi-threaded applications with our Java Concurrency guide:

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eBook – Java Streams – NPI EA (cat=Java Streams)
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Since its introduction in Java 8, the Stream API has become a staple of Java development. The basic operations like iterating, filtering, mapping sequences of elements are deceptively simple to use.

But these can also be overused and fall into some common pitfalls.

To get a better understanding on how Streams work and how to combine them with other language features, check out our guide to Java Streams:

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