Bug: java-client can not get error message when go-server return error

[chenleirr]

My code is as follows

go-server

java-client

The problem is that exception java catched is not contain the go error message which should be ‘invalid params: uid, name, cert could not be empty’.

In fact, java-client always catch as follows:

Failed to invoke the method Init in the service com.xxx.service.go.base.certify.api.CertifyService. Tried 1 times of the providers [10.71.8.70:20001] (1/1) from the registry 10.71.8.70:2181 on the consumer 10.71.8.70 using the dubbo version 2.6.3. Last error is: Failed to invoke remote method: Init, provider: dubbo://10.71.8.70:20001/com.xxx.service.go.base.certify.api.CertifyService?anyhost=true&app.version=1.0&application=consumer-of-certify-app&category=providers&check=false&cluster=failover&dubbo=dubbo-provider-golang-2.6.0&environment=dev&group=&interface=com.xxx.service.go.base.certify.api.CertifyService&ip=192.168.99.1&loadbalance=random&methods=Init&methods.Init.loadbalance=random&methods.Init.retries=3&methods.Init.weight=0&module=dubbogo+certify+server&name=CertifyService&organization=test.com&owner=raychen&pid=71023&register.ip=10.71.8.70&remote.timestamp=1559621785&retries=0&service.filter=echo&side=consumer&timestamp=1559622450690&version=&warmup=100, cause: 0

[hxmhlt]

We can discuss in here. @fangyincheng @wongoo

[hxmhlt]

related issue: https://github.com/dubbogo/hessian2/issues/53

[hxmhlt]

Can we convert error in Go to exception in Java instead of Golang developers have to register a java pojo 'Exception' . ? I think both error in Go & Exception in Java is basic type .

[fangyincheng]

Now, I think there are two ways:

1. In hessian2, we can decode it as error when decoding a exception.
2. RegisterPOJO! Define some Exception struct(eg: IOException、RemotingException etc.). We can define a Exception struct named Exception, and then, users need to define their own XxxException. But many exception class of java SDK will must be define by users.

What do you think?

[hxmhlt]

Maybe we can do both. User can define the java exception POJO in go and register it. Also we can provide some standard POJOs of java exception that are often used instead of all of them. If Hessian2 finds neither the standard POJO corresponding to exception nor the user-defined-registered one, then Hessian2 can decode exception as error in go through the rules we define.