code: public Future<AuthenticationResult> acquireToken(final String resource,
              final AsymmetricKeyCredential credential,
              final AuthenticationCallback callback)
              throws AuthenticationException {
          return this.acquireToken(resource, JwtHelper.buildJwt(credential,
                  this.authenticationAuthority.getSelfSignedJwtAudience()),
                  callback);
      }
docs: Acquires security token from the authority.
  
  @param resource
  Identifier of the target resource that is the recipient of the
  requested token.
  @param credential
  object representing Private Key to use for token acquisition.
  @param callback
  optional callback object for non-blocking execution.
  @return A {@link Future} object representing the
  {@link AuthenticationResult} of the call. It contains Access
  Token and the Access Token's expiration time. Refresh Token
  property will be null for this overload.
  @throws AuthenticationException {@link AuthenticationException}