Configuration issue? Exception at peerConnection.setRemoteDescription

[yvanzine]

Summary of the issue:

0. Environment:
   WSL, Ubuntu 22.04, version 0.10.0
   0.1) Ran RTCPeerConnectionTests to great success from master
1. Imported library into a maven-eclipse project.

<dependency>
    <groupId>dev.onvoid.webrtc</groupId>
    <artifactId>webrtc-java</artifactId>
    <version>0.10.0</version>
</dependency>

2. Executed as part of handle offer:

RTCSessionDescription offer = gson.fromJson(json, RTCSessionDescription.class);
AudioDeviceModule audioDevModule = new AudioDeviceModule(AudioLayer.kDummyAudio);
PeerConnectionFactory factory = new PeerConnectionFactory(audioDevModule);
RTCConfiguration config = new RTCConfiguration();
RTCPeerConnection peerConnection = factory.createPeerConnection(config, candidate -> {});
RTCConfiguration peerConfig = peerConnection.getConfiguration();
System.out.println("peerConfig: " + peerConfig);
try {
      	System.out.println("peerConnection class: " + peerConnection.getClass());
      	System.out.println("peerConnection.toString(): " + peerConnection);
      	System.out.println("peerConnection state: " + peerConnection.getConnectionState());
      	System.out.println("peerConnection ice state: " + peerConnection.getIceConnectionState());
        // answer
        var setObserver = new RendererSetDescObserver();
        peerConnection.setRemoteDescription(offer, setObserver);
        setObserver.get();
...

3. Getting the following exception:

📡 Handling offer: {"offer":{...}
peerConfig: dev.onvoid.webrtc.RTCConfiguration@74b9b536
/usr/java/packages/lib:/usr/lib/x86_64-linux-gnu/jni:/lib/x86_64-linux-gnu:/usr/lib/x86_64-linux-gnu:/usr/lib/jni:/lib:/usr/lib
peerConnection class: class dev.onvoid.webrtc.RTCPeerConnection
peerConnection.toString(): dev.onvoid.webrtc.RTCPeerConnection@5f91ce8b
peerConnection state: NEW
peerConnection ice state: NEW
Exception in thread "EventThread" java.lang.NullPointerException
	at dev.onvoid.webrtc.RTCPeerConnection.setRemoteDescription(Native Method)
	at WebRTCRenderer.handleOffer(WebRTCRenderer.java:195)
	at WebRTCRenderer.lambda$1(WebRTCRenderer.java:65)
	at io.socket.emitter.Emitter.emit(Emitter.java:117)
	at io.socket.client.Socket.onevent(Socket.java:320)
	at io.socket.client.Socket.onpacket(Socket.java:271)
	at io.socket.client.Socket.access$100(Socket.java:18)
	at io.socket.client.Socket$2$2.call(Socket.java:88)
	at io.socket.emitter.Emitter.emit(Emitter.java:117)
	at io.socket.client.Manager.ondecoded(Manager.java:361)
	at io.socket.client.Manager.access$1200(Manager.java:22)
	at io.socket.client.Manager$5.call(Manager.java:355)
	at io.socket.parser.IOParser$Decoder.add(IOParser.java:103)
	at io.socket.client.Manager$2.call(Manager.java:331)
	at io.socket.emitter.Emitter.emit(Emitter.java:117)
	at io.socket.engineio.client.Socket.onPacket(Socket.java:558)
	at io.socket.engineio.client.Socket.access$1000(Socket.java:36)
	at io.socket.engineio.client.Socket$5.call(Socket.java:337)
	at io.socket.emitter.Emitter.emit(Emitter.java:117)
	at io.socket.engineio.client.Transport.onPacket(Transport.java:124)
	at io.socket.engineio.client.Transport.onData(Transport.java:116)
	at io.socket.engineio.client.transports.WebSocket.access$100(WebSocket.java:23)
	at io.socket.engineio.client.transports.WebSocket$1$2.run(WebSocket.java:73)
	at io.socket.thread.EventThread$2.run(EventThread.java:80)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:829)
java.lang.NullPointerException
	at dev.onvoid.webrtc.RTCPeerConnection.setRemoteDescription(Native Method)
	at WebRTCRenderer.handleOffer(WebRTCRenderer.java:195)
	at WebRTCRenderer.lambda$1(WebRTCRenderer.java:65)
	at io.socket.emitter.Emitter.emit(Emitter.java:117)
	at io.socket.client.Socket.onevent(Socket.java:320)
	at io.socket.client.Socket.onpacket(Socket.java:271)
	at io.socket.client.Socket.access$100(Socket.java:18)
	at io.socket.client.Socket$2$2.call(Socket.java:88)
	at io.socket.emitter.Emitter.emit(Emitter.java:117)
	at io.socket.client.Manager.ondecoded(Manager.java:361)
	at io.socket.client.Manager.access$1200(Manager.java:22)
	at io.socket.client.Manager$5.call(Manager.java:355)
	at io.socket.parser.IOParser$Decoder.add(IOParser.java:103)
	at io.socket.client.Manager$2.call(Manager.java:331)
	at io.socket.emitter.Emitter.emit(Emitter.java:117)
	at io.socket.engineio.client.Socket.onPacket(Socket.java:558)
	at io.socket.engineio.client.Socket.access$1000(Socket.java:36)
	at io.socket.engineio.client.Socket$5.call(Socket.java:337)
	at io.socket.emitter.Emitter.emit(Emitter.java:117)
	at io.socket.engineio.client.Transport.onPacket(Transport.java:124)
	at io.socket.engineio.client.Transport.onData(Transport.java:116)
	at io.socket.engineio.client.transports.WebSocket.access$100(WebSocket.java:23)
	at io.socket.engineio.client.transports.WebSocket$1$2.run(WebSocket.java:73)
	at io.socket.thread.EventThread$2.run(EventThread.java:80)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:829)

4. Please provide suggestions, I would really like it to be something so simple as a missed step in configuration?

Cheers

[yvanzine]

Explanation of the issue is below.

Offer or Answer json fields are named differently between javascript and webrtc-java libraries. Webrtc-java offer uses sdpType="offer" field and the standard field is type="offer". When json is exchanged with javascript clients and RTCSessionDescription is deserialized, this exception is thrown. This could be a limitation of Java wanting "type" for itself.

[devopvoid]

You get a NullPointerException in setRemoteDescription. You have to investigate that on your own. I will not fix bugs here.