Error: OAuth2Credentials instance does not support refreshing the access token. How to create a AccessToken instance with token value string?

I am working on streaming speech to text by using Google Speech to Text service on Android. Here is official sample repository. The sample runs successfully. But Alternatively, you should get the access token on the server side, and supply client app with it.

So I set up a server and create RESTful api for app to get the access token. {"token":"1234567890sdertyuikjhgfghjk....."}

And also use api: https://www.googleapis.com/oauth2/v1/tokeninfo?access_token={token} to get the token info:

{
 "issued_to": "102073270616313859663",
 "audience": "102073270616313859663",
 "scope": "https://www.googleapis.com/auth/cloud-platform",
 "expires_in": 3600,
 "access_type": "offline"
}

Then create a AccessToken instance: AccessToken token = new AccessToken(tokenValue, expiresIn);

But following error:

07-04 20:14:07.395 3023-3067/com.google.cloud.android.speech E/SpeechService: Error calling the API.
io.grpc.StatusRuntimeException: UNKNOWN
    at io.grpc.Status.asRuntimeException(Status.java:543)
    at io.grpc.stub.ClientCalls$StreamObserverToCallListenerAdapter.onClose(ClientCalls.java:395)
    at io.grpc.ClientInterceptors$CheckedForwardingClientCall.start(ClientInterceptors.java:202)
    at io.grpc.stub.ClientCalls.startCall(ClientCalls.java:276)
    at io.grpc.stub.ClientCalls.asyncStreamingRequestCall(ClientCalls.java:266)
    at io.grpc.stub.ClientCalls.asyncBidiStreamingCall(ClientCalls.java:106)
    at com.google.cloud.speech.v1.SpeechGrpc$SpeechStub.streamingRecognize(SpeechGrpc.java:217)
    at com.google.cloud.android.speech.SpeechService.startRecognizing(SpeechService.java:264)
    at com.google.cloud.android.speech.MainActivity$1.onVoiceStart(MainActivity.java:62)
    at com.google.cloud.android.speech.VoiceRecorder$ProcessVoice.run(VoiceRecorder.java:199)
    at java.lang.Thread.run(Thread.java:764)
 Caused by: java.lang.IllegalStateException: OAuth2Credentials instance does not support refreshing the access token. An instance with a new access token should be used, or a derived type that supports refreshing.
    at com.google.auth.oauth2.OAuth2Credentials.refreshAccessToken(OAuth2Credentials.java:208)
    at com.google.auth.oauth2.OAuth2Credentials.refresh(OAuth2Credentials.java:175)
    at com.google.auth.oauth2.OAuth2Credentials.getRequestMetadata(OAuth2Credentials.java:161)
    at com.google.cloud.android.speech.SpeechService$GoogleCredentialsInterceptor.getRequestMetadata(SpeechService.java:532)
    at com.google.cloud.android.speech.SpeechService$GoogleCredentialsInterceptor.access$900(SpeechService.java:450)
    at com.google.cloud.android.speech.SpeechService$GoogleCredentialsInterceptor$1.checkedStart(SpeechService.java:474)
    at io.grpc.ClientInterceptors$CheckedForwardingClientCall.start(ClientInterceptors.java:194)
    at io.grpc.stub.ClientCalls.startCall(ClientCalls.java:276) 
    at io.grpc.stub.ClientCalls.asyncStreamingRequestCall(ClientCalls.java:266) 
    at io.grpc.stub.ClientCalls.asyncBidiStreamingCall(ClientCalls.java:106) 
    at com.google.cloud.speech.v1.SpeechGrpc$SpeechStub.streamingRecognize(SpeechGrpc.java:217) 
    at com.google.cloud.android.speech.SpeechService.startRecognizing(SpeechService.java:264) 
    at com.google.cloud.android.speech.MainActivity$1.onVoiceStart(MainActivity.java:62) 
    at com.google.cloud.android.speech.VoiceRecorder$ProcessVoice.run(VoiceRecorder.java:199) 
    at java.lang.Thread.run(Thread.java:764) 

I could use the sample code:

 final InputStream stream = getResources().openRawResource(R.raw.credential);
 final GoogleCredentials credentials = 
 GoogleCredentials.fromStream(stream).createScoped(SCOPE);
 final AccessToken token = credentials.refreshAccessToken();

and get a working Token, and get its token value by using getTokenValue() and get it expiration time by getExpirationTime. Then create a Token instance: AccessToken token = new AccessToken(tokenValue, expiresIn); to return a AccessToken instance. But it will cause the same error.

So my question is that how to create an working AccessToken instance when I get the token value string and the expiration time.

from Error: OAuth2Credentials instance does not support refreshing the access token. How to create a AccessToken instance with token value string?