For Java code we use Spotless to format the code to comply with Avro's code style conventions (see above). Automatic formatting relies on Avro's Eclipse JDT formatter definition and is checked by maven at compile time. You can use the same definition to auto format from Eclipse or from IntelliJ configuring the Eclipse formatter plugin.
If you use maven code styles issues are checked at the compile phase. If your code breaks because of bad formatting, you must can format it automatically by running the command:
> mvn com.diffplug.spotless:spotless-maven-plugin:1.20.0:apply
Please make sure that all unit tests succeed before constructing your patch and that no new compiler warnings are introduced by your patch. Each language has its own directory and test process.