There are several ways to converting 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.

String.join() Method

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:

List<String> list = List.of("🌴", "🌱", "🍂", "🌷", "🌵");

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

System.out.println(str);
// 🌴,🌱,🍂,🌷,🌵

Java Streams

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

List<String> list = List.of("🌴", "🌱", "🍂", "🌷", "🌵");

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

System.out.println(str);
// 🌴,🌱,🍂,🌷,🌵

Apache Commons Lang

Finally, the last way to convert a list of string into a comma-separated string is by using the Apache Commons Lang's StringUtils.join() method:

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:

<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:

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

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