Class loader issues trying to add gwt-jackson as encoder/decoder

[Lucas Machado]

I am currently working on this issue https://github.com/resty-gwt/resty-gwt/issues/310 and i can use some help.

At this point i define a new property

<define-property name="restygwt.encodeDecode.useGwtJackson" values="true,false" />

And with a few changes on restygwt i was able to generate new EncodersDecoders based on GWT Jackson. :)

The modified source code is available here https://github.com/lucasam/resty-gwt

I am currently able to compile this new version and add it as dependency to a small gwt project that basically make 8 different async requests and print the results.

This small project works fine.

The source of this project can be found here https://github.com/lucasam/jaxson_example

The problem is

When i try to add a new test case identical to BasicTestGwt but with the useGwtJackson property equals to true I get the following message

[INFO] Running all GwtTestCases but AnnotationResolver

[INFO] logging for HtmlUnit thread

[INFO]    [WARN] Expected content type of 'application/javascript' or 'application/ecmascript' for remotely loaded JavaScript element at 'http://172.17.0.2:54217/org.fusesource.restygwt.BasicGwtJacksonTestGwt.JUnit/org.fusesource.restygwt.BasicGwtJacksonTestGwt.JUnit.nocache.js', but got 'application/x-javascript'.

[INFO] Rebinding com.google.gwt.core.client.impl.SchedulerImpl

[INFO]    Checking rule <replace-with class='com.github.nmorel.gwtjackson.client.JsonSerializationContext.DefaultBuilder'/>

[INFO]       [WARN] Unknown type 'com.github.nmorel.gwtjackson.client.JsonSerializationContext.Builder' specified in deferred binding rule

[INFO]    Checking rule <generate-with class='com.github.nmorel.gwtjackson.rebind.ObjectMapperGenerator'/>

[INFO]       [WARN] Unknown type 'com.github.nmorel.gwtjackson.client.ObjectWriter' specified in deferred binding rule

[INFO] Rebinding com.google.gwt.junit.client.impl.JUnitHost

[INFO]    Checking rule <replace-with class='com.github.nmorel.gwtjackson.client.JsonSerializationContext.DefaultBuilder'/>

[INFO]       [WARN] Unknown type 'com.github.nmorel.gwtjackson.client.JsonSerializationContext.Builder' specified in deferred binding rule

[INFO]    Checking rule <generate-with class='com.github.nmorel.gwtjackson.rebind.ObjectMapperGenerator'/>

[INFO]       [WARN] Unknown type 'com.github.nmorel.gwtjackson.client.ObjectWriter' specified in deferred binding rule

[INFO] Rebinding com.google.gwt.user.client.impl.WindowImpl

[INFO]    Checking rule <replace-with class='com.github.nmorel.gwtjackson.client.JsonSerializationContext.DefaultBuilder'/>

[INFO]       [WARN] Unknown type 'com.github.nmorel.gwtjackson.client.JsonSerializationContext.Builder' specified in deferred binding rule

[INFO]    Checking rule <generate-with class='com.github.nmorel.gwtjackson.rebind.ObjectMapperGenerator'/>

[INFO]       [WARN] Unknown type 'com.github.nmorel.gwtjackson.client.ObjectWriter' specified in deferred binding rule

[INFO] Rebinding org.fusesource.restygwt.client.basic.ExampleService

[INFO]    Adding '2' new generated units

[INFO]       Resolving org.fusesource.restygwt.client.basic.ExampleDto_Gen_GwtJackEncDec_.GwtJackMapper

[INFO]          Found type 'org.fusesource.restygwt.client.basic.ExampleDto_Gen_GwtJackEncDec_.GwtJackMapper'

[INFO]             [ERROR] Unable to resolve class com/github/nmorel/gwtjackson/client/ObjectMapper

[INFO] Rebinding com.google.gwt.logging.client.LogConfiguration.LogConfigurationImplNull

[INFO]    Checking rule <replace-with class='com.github.nmorel.gwtjackson.client.JsonSerializationContext.DefaultBuilder'/>

[INFO]       [WARN] Unknown type 'com.github.nmorel.gwtjackson.client.JsonSerializationContext.Builder' specified in deferred binding rule

[INFO]    Checking rule <generate-with class='com.github.nmorel.gwtjackson.rebind.ObjectMapperGenerator'/>

[INFO]       [WARN] Unknown type 'com.github.nmorel.gwtjackson.client.ObjectWriter' specified in deferred binding rule

[INFO] Rebinding org.fusesource.restygwt.client.basic.ExampleDto_Gen_GwtJackEncDec_.GwtJackMapper

[INFO]    Checking rule <replace-with class='com.github.nmorel.gwtjackson.client.JsonSerializationContext.DefaultBuilder'/>

[INFO]       [WARN] Unknown type 'com.github.nmorel.gwtjackson.client.JsonSerializationContext.Builder' specified in deferred binding rule

[INFO]    Checking rule <generate-with class='com.github.nmorel.gwtjackson.rebind.ObjectMapperGenerator'/>

[INFO]       [WARN] Unknown type 'com.github.nmorel.gwtjackson.client.ObjectWriter' specified in deferred binding rule

[INFO] [ERROR] Deferred binding result type 'org.fusesource.restygwt.client.basic.ExampleDto_Gen_GwtJackEncDec_.GwtJackMapper' should not be abstract

[INFO] Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 13.186 sec <<< FAILURE!

We can observe classloader issues on the beggining of the process

[INFO]    Checking rule <replace-with class='com.github.nmorel.gwtjackson.client.JsonSerializationContext.DefaultBuilder'/>

[INFO]       [WARN] Unknown type 'com.github.nmorel.gwtjackson.client.JsonSerializationContext.Builder' specified in deferred binding rule

And finally 

[INFO] Rebinding org.fusesource.restygwt.client.basic.ExampleService

[INFO]    Adding '2' new generated units

[INFO]       Resolving org.fusesource.restygwt.client.basic.ExampleDto_Gen_GwtJackEncDec_.GwtJackMapper

[INFO]          Found type 'org.fusesource.restygwt.client.basic.ExampleDto_Gen_GwtJackEncDec_.GwtJackMapper'

[INFO]             [ERROR] Unable to resolve class com/github/nmorel/gwtjackson/client/ObjectMapper

 

I already inspected the generated classes and it is fine. 

I already inspected the maven with -X and the gwt-jackson jars are in the classpath.

The same behavior is present in other bigger gwt project with a large set of dependencies. As so i am not inclined to believe that this is a GWTTestCase issue but a classloader issue with gwt-jackson.

GWT jackson has this open bug https://github.com/nmorel/gwt-jackson/issues/41 which I was inclined to blame, but i already re-compiled everything with openjdk7 and the problem persists.

I currently believe that there is some dependency that is preventing gwt-jackson from loading.

Does anyone have some clue about what is going on? 

--

Lucas Machado

[christian]

great news. I will have brief look tomorrow morning my time otherwise give me a day or two to find some more time for it. thanks for taking this one up - it feels like a big step forward for restygwt.

- christian

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[christian]

strange error indeed as all looks OK.

what about just using your https://github.com/lucasam/jaxson_example and add it as integration in restygwt/src/it/gwt-jackson

which would serve as start but still we need to find the problem as you say it  affects bigger projects.

[christian]

the problem is that we declare jackson-xzy dependencies with restygwt/pom.xml as well and pick version 2.5.3 and gwt-jackson uses some (not all) but with version 2.7.2

I am sure once you cleaned up the dependency tree and maybe use the dependencies from gwt-jackson or so, things will work.

- christian

[Lucas Machado]

well
about your suggestion. Let me work on it a little more. I am not ready to give up yet :)

I will add deps on the project jaxson_example util it breaks to try to find the source of the problem.
And will try to get help with gwt-jackson guys also.

If anyone has some clue please let me know

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Lucas Machado

[christian]

submitted a small PR to your branch which fixes the dependencies :)