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

Partner – Microsoft – NPI EA (cat = Baeldung)
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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.

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.

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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 – Guide Spring Cloud – NPI EA (cat=Spring Cloud)
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eBook – Mockito – NPI EA (tag = Mockito)
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Mocking is an essential part of unit testing, and the Mockito library makes it easy to write clean and intuitive unit tests for your Java code.

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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.

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Spring 5 added support for reactive programming with the Spring WebFlux module, which has been improved upon ever since. Get started with the Reactor project basics and reactive programming in Spring Boot:

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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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eBook – Jackson – NPI EA (cat=Jackson)
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Course – LS – NPI EA (cat=Jackson)
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Explore Spring Boot 3 and Spring 6 in-depth through building a full REST API with the framework:

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Course – LSS – NPI EA (cat=Spring Security)
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Yes, Spring Security can be complex, from the more advanced functionality within the Core to the deep OAuth support in the framework.

I built the security material as two full courses - Core and OAuth, to get practical with these more complex scenarios. We explore when and how to use each feature and code through it on the backing project.

You can explore the course here:

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Course – All Access – NPI EA (cat= Spring)
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All Access is finally out, with all of my Spring courses. Learn JUnit is out as well, and Learn Maven is coming fast. And, of course, quite a bit more affordable. Finally.

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Course – LSD – NPI EA (tag=Spring Data JPA)
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Spring Data JPA is a great way to handle the complexity of JPA with the powerful simplicity of Spring Boot.

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Partner – LambdaTest – NPI EA (cat=Testing)
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End-to-end testing is a very useful method to make sure that your application works as intended. This highlights issues in the overall functionality of the software, that the unit and integration test stages may miss.

Playwright is an easy-to-use, but powerful tool that automates end-to-end testing, and supports all modern browsers and platforms.

When coupled with LambdaTest (an AI-powered cloud-based test execution platform) it can be further scaled to run the Playwright scripts in parallel across 3000+ browser and device combinations:

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Course – Spring Sale 2025 – NPI EA (cat= Baeldung)
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Course – Spring Sale 2025 – NPI (cat=Baeldung)
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1. Overview

There are many ways to count the number of occurrences of a char in a String in Java.

In this quick tutorial, we’ll focus on a few examples of how to count characters — first with the core Java library and then with other libraries and frameworks such as Spring and Guava.

Further reading:

Using indexOf to Find All Occurrences of a Word in a String

Learn how to solve the "needle in a haystack" problem by using the indexOf method to find all occurrences of a word in a larger text string.

Guava CharMatcher

Use the Guava CharMatcher to work with Strings - remove special chars, validate, trim, collapse, replace and count among other super useful APIs.

String Processing with Apache Commons Lang 3

Quick intro to working with Strings with the Apache Commons library and StringUtils.

2. Using Core Java Lib

2.1. Imperative Approach

Some developers may prefer to use core Java. There are many ways for counting the number of occurrences of a char in a String.

Let’s start with a simple/naive approach:

String someString = "elephant";
char someChar = 'e';
int count = 0;
 
for (int i = 0; i < someString.length(); i++) {
    if (someString.charAt(i) == someChar) {
        count++;
    }
}
assertEquals(2, count);

Not surprisingly, this will work, but there are better ways to do this.

2.2. Using Recursion

A less obvious but still interesting solution is to use recursion:

private static int useRecursion(
  String someString, char searchedChar, int index) {
    if (index >= someString.length()) {
        return 0;
    }
    
    int count = someString.charAt(index) == searchedChar ? 1 : 0;
    return count + useRecursion(
      someString, searchedChar, index + 1);
}

We can invoke this recursive method in the following way: useRecursionToCountChars(“elephant”, ‘e’, 0).

2.3. Using Regular Expressions

Another way would be to use regular expressions:

Pattern pattern = Pattern.compile("[^e]*e");
Matcher matcher = pattern.matcher("elephant");
int count = 0;
while (matcher.find()) {
    count++;
}
 
assertEquals(2, count);

Just note that this solution is technically correct but sub-optimal, as it’s overkill to use the very powerful regular expressions to solve such a simple problem as finding the number of occurrences of a character in a string.

2.4. Using Java 8 Features

New features available in Java 8 can be very helpful here.

Let’s use streams and lambdas to implement the count:

String someString = "elephant";
long count = someString.chars().filter(ch -> ch == 'e').count();
assertEquals(2, count);

long count2 = someString.codePoints().filter(ch -> ch == 'e').count();
assertEquals(2, count2);

So, this is clearly a cleaner and more readable solution using the core library.

3. Using External Libraries

Let’s now look at a few solutions that make use of utilities from external libraries.

3.1. Using StringUtils

In general, it is always better to use an existing solution instead of inventing our own. The commons.lang.StringUtils class provides us with the countMatches() method, which can be used for counting chars or even sub-strings in given String.

First, we need to include the appropriate dependency:

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.12.0</version>
</dependency>

We can find the latest version on Maven Central.

Let’s now use countMatches() to count the number of e characters in the “elephant” String literal:

int count = StringUtils.countMatches("elephant", "e");
assertEquals(2, count);

3.2. Using Guava

Guava can also be helpful in counting chars. We need to define the dependency:

<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>31.0.1-jre</version>
</dependency>

We can find the latest version on Maven Central.

Let’s see how Guava can quickly help us to count chars:

int count = CharMatcher.is('e').countIn("elephant");
assertEquals(2, count);

3.3. Using Spring

Naturally, adding the Spring Framework into our project just to count chars doesn’t make sense.

However, if we already have it in our project, we just need to use the countOccurencesOf() method:

int count = StringUtils.countOccurrencesOf("elephant", "e");
assertEquals(2, count);

4. Conclusion

In this article, we focused on various ways to count chars in the String. Some of them were designed purely in Java; some required additional libraries.

Our recommendation is to use already existing utilities from StringUtils, Guava or Spring. However, this article offers some possibilities to get it done with Java 8 if using only plain Java is preferred.

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:

>> Download the eBook

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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eBook – Persistence – NPI EA (cat=Persistence)
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Working on getting your persistence layer right with Spring?

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Course – LS – NPI EA (cat=REST)

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Get started with Spring Boot and with core Spring, through the Learn Spring course:

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Course – Spring Sale 2025 – NPI EA (cat= Baeldung)
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Yes, we're now running our Spring Sale. All Courses are 25% off until 26th May, 2025:

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Course – Spring Sale 2025 – NPI (All)
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eBook Jackson – NPI EA – 3 (cat = Jackson)