move bulk users upload from local db to azure b2c active directory in JAVA

I am trying to make a console app in java through which I want to migrate more than 100000 users to Azure AD B2C.

We are using Graph API for this purpose.

I have created a JSON format file which has a list of users, looks like below :

{
  "users": [
    {
      "displayName": "Amanda Polly",
      "givenName": "Amanda",
      "surname": "Polly",
      "extension_user_type": "user",
      "identities": [
        {
          "signInType": "emailAddress",
          "issuerAssignedId": "amandapolly@gmail.com"
        }
      ],
      "extension_timezone": "PST",
      "extension_locale": "en-US",
      "extension_tenant": "EG1234"
    },
    {
      "displayName": "Lowa Doe",
      "givenName": "Lowa",
      "surname": "Doe",
      "extension_user_type": "user",
      "identities": [
        {
          "signInType": "userName",
          "issuerAssignedId": "lowadow123"
        }
      ],
      "extension_timezone": "PST",
      "extension_locale": "en-US",
      "extension_tenant": "EG1234"
    }
   ]
}

I have this in a (dot)json file, i have to use this file and create users in b2c active directory using graph API, need help in starting.

User graph api and send a post request, like this

Set all the fields and then work it out like this.

User createNewUser = new User();
        createNewUser.displayName = displayName;
        
        if (givenName.equals(null) || givenName.isEmpty() || givenName.equals("") || givenName.equals(" ")) {
            LOG.warn("givenName is empty");
        } else {
            createNewUser.givenName = givenName;
        }
        
        if (surname.equals(null) || surname.isEmpty() || surname.equals("") || surname.equals(" ")) {
            LOG.warn("surname is empty");
        } else {
            createNewUser.surname = surname;
        }
        
        final LinkedList<ObjectIdentity> identitiesList = new LinkedList<ObjectIdentity>();
        ObjectIdentity identities = new ObjectIdentity();
        
        identities.signInType = signInType;
        identities.issuerAssignedId = issuerAssignedId;
        identities.issuer = "controlme.onmicrosoft.com";
        identitiesList.add(identities);

        createNewUser.identities = identitiesList;

        PasswordProfile passwordProfile = new PasswordProfile();
        passwordProfile.password = generatePassword(15);
        passwordProfile.forceChangePasswordNextSignIn = false;

        createNewUser.passwordProfile = passwordProfile;
        createNewUser.passwordPolicies = "DisablePasswordExpiration";
    

User buildUserRequest = graphClient.users()
                .buildRequest()
                .post(createNewUser);