Can't get it work with maven project

### Problems

I'm trying to build codeql with Webgoat. mvn build succeed, but no source code detected

### Steps to reproduct

1. git clone https://github.com/WebGoat/WebGoat.git
2. codeql database create java-database -l=java -c="mvn package -DskipTests=true"

Results

```
Finalizing database at /tmp/WebGoat/java-database.
No source code was seen and extracted to /tmp/WebGoat/java-database.
This can occur if the specified build commands failed to compile or process any code.
- Confirm that there is some source code for the specified language in the project.
- For codebases written in Go, JavaScript, TypeScript, and Python, do not specify
an explicit --command.
- For other languages, the --command must specify a "clean" build which compiles
all the source code files without reusing existing build artefacts.
```