# Java lang no class definition found

![](/files/-LAO3VWB485m02eQe585)

This error appears if the version of Java installed on your computer is not the one required by TRACER, which is Java 8. To fix the error, download and install Java 8. Once installed, open the terminal and type `java -version` and press `ENTER` to check you have the correct version installed; the version number should start with a `1` and the second number should be an `8`. If your second number is not `8`, then installation of Java 8 was not successful.

Once Java 8 is installed on your computer you can re-run TRACER.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://tracer.gitbook.io/manual/support/troubleshooting/java-lang-no-class-definition-found.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.