How can I receive git repository from plugin?

First, you need to add git4idea.jar plugin to your dependencies.
(By adding it as a provided library / to SDK and appending `<depends>Git4Idea</depends>` to plugin.xml)
You can locate it in /plugins/ folder of IDE distribution.

Next, you can use 
`GitRepositoryManager.getInstance(project).getRepositories()` to get configured git roots.
`GitRepository.getRemotes()` to get list of remotes in root.
`GitRemote.getUrls()` to get urls for a remote.

Thank you for your reply.

I tried to get Repositories with GitRepositoryManager, but I cannot get repositories.

It is because the repositories can be got after initializing ProjectLevelVcsManager's myMapping.

myMapping is NewMapping class.

This constructor end like this.

vcsManager.addInitializationRequest(VcsInitObject.MAPPINGS, (DumbAwareRunnable)() -> {
  if (!myProject.isDisposed()) {
    activateActiveVcses();
  }
});

I'm not sure what these code means.

But I understand this mappings only can be activated after vcsManager's initialization process.

So, I create the code

    ((ProjectLevelVcsManagerImpl)ProjectLevelVcsManager.getInstance(project)).addInitializationRequest(VcsInitObject.AFTER_COMMON, new Runnable() {
      @Override
      public void run() {
        Collection<Repository> repositories = VcsRepositoryManager.getInstance(project).getRepositories();
        System.out.println(repositories);
      }
    });

(Only ProjectLevelVcsManagerImpl) has `addInitializationRequest`...)

This code will wait VCSManager initialization process.

So, I can get repositories safely.

I feel this code is a bit tricky. Is there any other way to get repositories safely?

Probably, it's better to listen for all repository mappings changes (ex: if new root was added by user).
Ex:

project.getMessageBus().connect([disposable]).subscribe(VcsRepositoryManager.VCS_REPOSITORY_MAPPING_UPDATED, () -> doSmth);

By the way, what are you trying to achieve?

Thank you for your advice.

I will change my code.

I want to build a github plugin for intellij.