How to Resolve java.nio.charset.UnmappableCharacterException in Jenkins Pipeline Builds

---

Understanding the Exception

Common Causes

Source Code Encoding: The source code uses an encoding that includes characters not supported by the target charset.

Configuration Issues: Misconfigured charset settings in your Jenkins job or pipeline script.

External File Encodings: Incorrect encoding in files being read or written by your build process.

Steps to Resolve UnmappableCharacterException

Identify the Problematic Encoding

First, identify the default encoding used by your Jenkins build environment. This can be done by adding a small step in your pipeline to print the default charset:

[[See Video to Reveal this Text or Code Snippet]]

Configure Source Code Encoding

Ensure that your source code files are saved using a charset that matches your Jenkins environment. UTF-8 is often a safe choice for many build environments. Make sure your text editor and version control system are configured to use UTF-8.

Set Explicit Charsets in Build Steps

If you know the specific charset your build script should be using, set it explicitly in the relevant build step. For instance, if you are compiling Java code with Maven, you can set the encoding property:

[[See Video to Reveal this Text or Code Snippet]]

Include Charset Parameters in Scripted Pipelines

If you are using scripted pipelines, you can set the charset explicitly in your code:

[[See Video to Reveal this Text or Code Snippet]]

Verify Charset of External Dependencies

If your build process reads from or writes to external files, verify that these files also use the expected charset. You can convert these files to a compatible encoding if necessary.

Jenkins Configuration

Check your Jenkins global configuration to ensure that it uses a consistent default charset:

Go to Manage Jenkins > System Configuration.

Set the correct system locale and charset.

Conclusion