uselist with Gson causes error "com.google.gson.JsonSyntaxException: Expected BEGIN_ARRAY but was BEGIN_OBJECT"

Issue

• When use Gson to unmarshal JSON,

<unmarshal>
    <json library="Gson" useList="true" />
</unmarshal>

• The following error is occurred.

com.google.gson.JsonSyntaxException: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 3 path $[0]
    at com.google.gson.Gson.fromJson(Gson.java:822)
    at com.google.gson.Gson.fromJson(Gson.java:748)
    at org.apache.camel.component.gson.GsonDataFormat.unmarshal(GsonDataFormat.java:105)
    at org.apache.camel.processor.UnmarshalProcessor.process(UnmarshalProcessor.java:69)
    at org.apache.camel.management.InstrumentationProcessor.process(InstrumentationProcessor.java:77)
    at org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:448)
    at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:191)
    at org.apache.camel.processor.Pipeline.process(Pipeline.java:121)
    at org.apache.camel.processor.Pipeline.process(Pipeline.java:83)
    at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:191)
    at org.apache.camel.component.direct.DirectProducer.process(DirectProducer.java:51)
    at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:191)
    at org.apache.camel.util.AsyncProcessorHelper.process(AsyncProcessorHelper.java:109)
    at org.apache.camel.processor.UnitOfWorkProducer.process(UnitOfWorkProducer.java:68)
    at org.apache.camel.impl.ProducerCache$2.doInProducer(ProducerCache.java:375)
    at org.apache.camel.impl.ProducerCache$2.doInProducer(ProducerCache.java:343)
    at org.apache.camel.impl.ProducerCache.doInProducer(ProducerCache.java:233)
    at org.apache.camel.impl.ProducerCache.sendExchange(ProducerCache.java:343)
    at org.apache.camel.impl.ProducerCache.send(ProducerCache.java:201)
    at org.apache.camel.impl.DefaultProducerTemplate.send(DefaultProducerTemplate.java:128)
    at org.apache.camel.impl.DefaultProducerTemplate.sendBody(DefaultProducerTemplate.java:132)
    at org.apache.camel.impl.DefaultProducerTemplate.requestBody(DefaultProducerTemplate.java:281)
    at com.mycompany.camel.blueprint.RouteTest.testRoute(RouteTest.java:32)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:55)
    at org.junit.rules.RunRules.evaluate(RunRules.java:20)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 3 path $[0]
    at com.google.gson.stream.JsonReader.beginArray(JsonReader.java:350)
    at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.read(MapTypeAdapterFactory.java:172)
    at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.read(MapTypeAdapterFactory.java:145)
    at com.google.gson.Gson.fromJson(Gson.java:810)
    ... 50 more