Using MSAL4J library with B2C can result in a JSON parse error due to an assumption in TokenResponse that doesn't always hold with B2C and that assumption is that an access token is always returned. The refresh token has the same assumption although perhaps that is fine? In the case where MSAL4J is used for a server-side application login that needs no custom scope then no access token is returned and this code should not blow up on that scenario.

https://github.com/AzureAD/microsoft-authentication-library-for-java/blob/dev/src/main/java/com/microsoft/aad/msal4j/TokenResponse.java#L48
final AccessToken accessToken = AccessToken.parse(jsonObject);
final RefreshToken refreshToken = RefreshToken.parse(jsonObject);