3

My Grails application and its integration tests are throwing a StackOverflowError when I try to use Groovy's JsonBuilder class on my domain classes. My code looks like this:

String result = new JsonBuilder(new MyDomainClass())

Since I found articles about JsonBuilder looping on self-references, I stripped down the domain class to almost nothing:

package com.mycompany.myapp.myarea
class MyDomainClass { }

but the stack overflow still reproduces. Here's the kicker. If I move the declaration of MyDomainClass out of its normal location and into the file where the unit test lives (i.e., take it out of its package), JsonBuilder works.

Stack trace below. Any help here?

Thanks, BGU

 java.lang.StackOverflowError
at java.security.AccessController.doPrivileged(Native Method)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.createCallStaticSite(CallSiteArray.java:62)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.createCallSite(CallSiteArray.java:159)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
at java_lang_Class$isArray.call(Unknown Source)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:135)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure2.doCall(JsonOutput.groovy:158)
at sun.reflect.GeneratedMethodAccessor974.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.callClosureForMapEntry(DefaultGroovyMethods.java:3870)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2426)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2443)
at org.codehaus.groovy.runtime.dgm$61.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:154)
at groovy.json.JsonOutput$toJson$0.callStatic(Unknown Source)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:146)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure1.doCall(JsonOutput.groovy:138)
at sun.reflect.GeneratedMethodAccessor978.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at groovy.lang.Closure.call(Closure.java:425)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2157)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2128)
at org.codehaus.groovy.runtime.dgm$59.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:138)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure2.doCall(JsonOutput.groovy:158)
at sun.reflect.GeneratedMethodAccessor974.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.callClosureForMapEntry(DefaultGroovyMethods.java:3870)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2426)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2443)
at org.codehaus.groovy.runtime.dgm$61.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:154)
at groovy.json.JsonOutput$toJson$0.callStatic(Unknown Source)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:146)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure1.doCall(JsonOutput.groovy:138)
at sun.reflect.GeneratedMethodAccessor978.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at groovy.lang.Closure.call(Closure.java:425)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2157)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2128)
at org.codehaus.groovy.runtime.dgm$59.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:138)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure2.doCall(JsonOutput.groovy:158)
at sun.reflect.GeneratedMethodAccessor974.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.callClosureForMapEntry(DefaultGroovyMethods.java:3870)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2426)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2443)
at org.codehaus.groovy.runtime.dgm$61.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:154)
at groovy.json.JsonOutput$toJson$0.callStatic(Unknown Source)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:146)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure1.doCall(JsonOutput.groovy:138)
at sun.reflect.GeneratedMethodAccessor978.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at groovy.lang.Closure.call(Closure.java:425)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2157)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2128)
at org.codehaus.groovy.runtime.dgm$59.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite.call(PojoMetaMethodSite.java:53)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at groovy.json.JsonOutput.toJson(JsonOutput.groovy:138)
at groovy.json.JsonOutput$toJson.callStatic(Unknown Source)
at groovy.json.JsonOutput$_toJson_closure2.doCall(JsonOutput.groovy:158)
at sun.reflect.GeneratedMethodAccessor974.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1082)
at groovy.lang.ExpandoMetaClass.invokeMethod(ExpandoMetaClass.java:1106)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:906)
at groovy.lang.Closure.call(Closure.java:412)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.callClosureForMapEntry(DefaultGroovyMethods.java:3870)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2426)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.collect(DefaultGroovyMethods.java:2443)
at org.codehaus.groovy.runtime.dgm$61.invoke(Unknown Source)
at org.codehaus.groovy.runtime.callsite.PojoMetaMethodSite$PojoMetaMethodSiteNoUnwrapNoCoerce.invoke(PojoMetaMethodSite.java:271)...
Blake Underwood
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1 Answers1

1

I stepped into the code a little bit, and JsonBuilder has a number of type checks to decide how the object should be written. In case of the domain class it matches Iterable. It then tries to loop over it and write each item etc.

Strange thing is that next after casting the object to Iterable returns the objects itself.... causing and endless loop.

It works if I write the following (still fails without the explicit cast):

String result = new JsonBuilder((Map)(new MyDomainClass().properties))
Martin Hauner
  • 1,593
  • 1
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  • 15
  • Thanks for the helpful tip. Unfortunately many of the values in my 'properties' map are, themselves, domain classes. Thus I just get the stack overflow in a different place. I'm new to Groovy, so I am wondering if JsonBuilder is the right tool for the job? Maybe there is a more class- (versus map-) friendly JSON generator floating around? Or is there a desire to get the bug you mentioned fixed? I'm open to suggestions. – Blake Underwood Aug 26 '14 at 22:32