How not to display the .class in git

Make sure your .class files were not already added to the index.
You would need to git rm -r --cached path/to/.classfiles/ those files first.
(they will still be on the disk, but no longer part of the git index, and will be ignored by the git status)

If you don't want any .class file versioned (but you didn't include them in the .gitignore initially), as Michal Stefanow comments below:

git rm -r --cached *.class

Mark adds in the comments:

For Windows TortoiseGit users like me, follow the instructions in this related post to do the git in the GUI

Right click that file, choose TortoiseGit -> Delete (keep local).
This does git rm --cached.

You probably actually want to add *.class into your .gitignore file, not .class - the former will match any class file (because of the wildcard *), whereas the latter only matches a file named exactly .class.

Create a new file named ./gitignore in your directory and add the following lines in that:

target/bin/!.mvn/wrapper/maven-wrapper.jar### STS ###.apt_generated.classpath.factorypath.project.settings.springBeans### IntelliJ IDEA ###.idea*.iws*.iml*.ipr### NetBeans ###nbproject/private/build/nbbuild/dist/nbdist/.nb-gradle/target/