added interface creation in JavaSourceCodeWriter

[philipAthanasopoulos]

It used to be that JavaTypeDeclaration could not be an interface. I added Interface in the typeModifiers and if the type declaration is an Interface, the "class" keyword is skipped.

[mhalbritter]

Please reformat the files by running mvn spring-javaformat:apply, thanks.

[philipAthanasopoulos]

I reformatted the code and mvn clean installruns successfully on my local environment.

[mhalbritter]

I looked at the diff, and this doesn't look right. For example, there are changes to initializr-web/src/main/java/io/spring/initializr/web/mapper/DependencyMetadataV21JsonMapper.java which have nothing to do with JavaTypeDeclaration. Please rebase your changes on top of main to get a clean diff.

[philipAthanasopoulos]

I reset my fork to upstream and pushed a single commit, hope its ok now

[mhalbritter]

Thanks for the PR. Unfortunately there's more to it than the code already implemented: Interfaces can't have fields, only some modifiers are applicable to them, implementing other interfaces is done with extends (vs. implements for classes), etc etc. And we'd need to implement this for Kotlin and for Groovy, too. I've created #1633 for that, and we need a thorough design how to integrate it.