# Convert a list to a comma-separated string in Java

By Atta Ur Rehman Shah (https://attacomsian.com/about). Published Jul 4, 2021, updated Oct 29, 2022. Topics: Java.
Canonical URL: https://attacomsian.com/blog/java-convert-list-to-comma-separated-string

> A quick guide to converting a list into a comma-separated string in Java.

There are several ways to convert a list into a comma-separated string in Java. You can use core Java functions, Steams API, and Apache Commons Lang to convert a list into a string.

## Convert a list to a comma-separated string using `String.join()`

The most common way to convert a list of strings into a comma-separated string is by using the static `join()` method from the `String` class:

```java
List<String> list = List.of("?", "?", "?", "?", "?");

String str = String.join(",", list);

System.out.println(str);
// ?,?,?,?,?
```

## Convert a list to a comma-separated string using Java streams

You can also use the Java Stream API to transform a list of strings into a comma-separated list, as shown below:

```java
List<String> list = List.of("?", "?", "?", "?", "?");

String str = list.stream().collect(Collectors.joining(","));

System.out.println(str);
// ?,?,?,?,?
```

## Convert a list to a comma-separated string using Apache Commons Lang

Finally, the last way to convert a list of strings into a comma-separated string is by using the [Apache Commons Lang](https://commons.apache.org/proper/commons-lang/)'s `StringUtils.join()` method:

```java
List<String> list = List.of("?", "?", "?", "?", "?");

String str = StringUtils.join(list, ',');

System.out.println(str);
// ?,?,?,?,?
```

Make sure to add the following dependency to the `pom.xml` file for a Maven project:

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

For Gradle, add the below dependency to your `build.gradle` file:

```groovy
implementation 'org.apache.commons:commons-lang3:12.0'
```

**Read Next:** [Convert a comma-separated string to a list in Java](https://attacomsian.com/blog/java-string-with-separator-to-list)