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Editorial Team
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Asked: 2026-05-14T14:35:50+00:00

I’m trying to learn about grails with Google App Engine and JPA by following

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I’m trying to learn about grails with Google App Engine and JPA by following a few tutorials:

I’ve got grails 1.3.0 RC 2, and App Engine SDK 1.3.3, and I’m using Windows 7. The steps that I try are:

  1. grails create-app appname
  2. cd appname
  3. grails install-plugin app-engine. I answer jpa when asked about jdo/jpa. It appears to install the gorm-jpa plugin automatically, although the tutorials all suggest installing gorm-jpa manually.
  4. grails install-plugin gorm-jpa (just in case)
  5. grails create-domain-class test.Person

  6. Edit the grails-app/domain/test/Person.groovy to add name and address fields:

    package test
import javax.persistence.*;

// import com.google.appengine.api.datastore.Key;
@Entity
class Person implements Serializable {
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  Long id

  @Basic
  String name

  @Basic
  String address

  static constraints = {
    id visible:false
  }
}

  7. grails generate-all test.Person

I get errors during this final step:

C:\Users\John\Workspaces\STS\appname>grails generate-all test.Person
Welcome to Grails 1.3.0.RC2 - http://grails.org/
Licensed under Apache Standard License 2.0
Grails home is set to: C:\Users\John\Downloads\grails-1.3.0.RC2\grails-1.3.0.RC2

Base Directory: C:\Users\John\Workspaces\STS\appname
Resolving dependencies...
Dependencies resolved in 493ms.
Running script C:\Users\John\Downloads\grails-1.3.0.RC2\grails-1.3.0.RC2\scripts\GenerateAll.groovy
Environment set to development
     [copy] Copied 4 empty directories to 2 empty directories under C:\Users\John\.grails\1.3.0.RC2\projects\appname\resources
     [copy] Copied 4 empty directories to 2 empty directories under C:\Users\John\.grails\1.3.0.RC2\projects\appname\resources
     [copy] Copied 1 empty directory to 1 empty directory under C:\Users\John\.grails\1.3.0.RC2\projects\appname\resources
    [mkdir] Created dir: C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\classes
  [groovyc] Compiling 12 source files to C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\classes
Note: C:\Users\John\.grails\1.3.0.RC2\projects\appname\plugins\gorm-jpa-0.7.1\src\java\org\grails\jpa\domain\JpaGrailsDomainClass.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
  [groovyc] Compiling 8 source files to C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\classes
    [mkdir] Created dir: C:\Users\John\.grails\1.3.0.RC2\projects\appname\resources\grails-app\i18n
[native2ascii] Converting 13 files from C:\Users\John\Workspaces\STS\appname\grails-app\i18n to C:\Users\John\.grails\1.3.0.RC2\projects\appname\resources\grails-app\i18n
    [mkdir] Created dir: C:\Users\John\.grails\1.3.0.RC2\projects\appname\resources\plugins\gorm-jpa-0.7.1\grails-app\i18n
    [mkdir] Created dir: C:\Users\John\.grails\1.3.0.RC2\projects\appname\resources\plugins\app-engine-0.8.10\grails-app\i18n
[native2ascii] Converting 1 file from C:\Users\John\.grails\1.3.0.RC2\projects\appname\plugins\gorm-jpa-0.7.1\grails-app\i18n to C:\Users\John\.grails\1.3.0.RC2\projects\appname\resources\plugins\gorm
-jpa-0.7.1\grails-app\i18n
[native2ascii] Converting 1 file from C:\Users\John\.grails\1.3.0.RC2\projects\appname\plugins\app-engine-0.8.10\grails-app\i18n to C:\Users\John\.grails\1.3.0.RC2\projects\appname\resources\plugins\a
pp-engine-0.8.10\grails-app\i18n
     [copy] Copying 1 file to C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\classes
     [copy] Copying 2 files to C:\Users\John\.grails\1.3.0.RC2\projects\appname\resources
     [copy] Copied 2 empty directories to 2 empty directories under C:\Users\John\.grails\1.3.0.RC2\projects\appname\resources
     [copy] Copying 1 file to C:\Users\John\.grails\1.3.0.RC2\projects\appname
    [mkdir] Created dir: C:\Users\John\Workspaces\STS\appname\web-app\plugins\app-engine-0.8.10
     [copy] Copying 1 file to C:\Users\John\Workspaces\STS\appname\web-app\plugins\app-engine-0.8.10
     [copy] Copying 1 file to C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF
    [mkdir] Created dir: C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\lib
     [copy] Copying 64 files to C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\lib
Configuring persistence for AppEngine
    [mkdir] Created dir: C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\classes\META-INF
     [copy] Copying 1 file to C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\classes\META-INF
    [mkdir] Created dir: C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\plugins\app-engine-0.8.10
     [copy] Copying 2 files to C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\plugins\app-engine-0.8.10
    [mkdir] Created dir: C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\plugins\gorm-jpa-0.7.1
     [copy] Copying 2 files to C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\plugins\gorm-jpa-0.7.1
Packaging AppEngine jar files
Enhancing JDO classes
  [enhance] DataNucleus Enhancer (version 1.1.4) : Enhancement of classes
  [enhance] DataNucleus Enhancer completed with success for 1 classes. Timings : input=589 ms, enhance=200 ms, total=789 ms. Consult the log for full details
  [groovyc] Compiling 1 source file to C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF\classes
     [copy] Copying 1 file to C:\Users\John\.grails\1.3.0.RC2\projects\appname
     [copy] Copying 1 file to C:\Users\John\Workspaces\STS\appname\web-app\WEB-INF
Configuring persistence for AppEngine
Packaging AppEngine jar files
Enhancing JDO classes
  [enhance] DataNucleus Enhancer (version 1.1.4) : Enhancement of classes
  [enhance] DataNucleus Enhancer completed with success for 1 classes. Timings : input=585 ms, enhance=28 ms, total=613 ms. Consult the log for full details
Generating views for domain class test.Person ...
java.lang.reflect.InvocationTargetException
        at SimpleTemplateScript1.run(SimpleTemplateScript1.groovy:43)
        at _GrailsGenerate_groovy.generateForDomainClass(_GrailsGenerate_groovy:85)
        at _GrailsGenerate_groovy$_run_closure1.doCall(_GrailsGenerate_groovy:50)
        at GenerateAll$_run_closure1.doCall(GenerateAll.groovy:42)
        at gant.Gant$_dispatch_closure5.doCall(Gant.groovy:381)
        at gant.Gant$_dispatch_closure7.doCall(Gant.groovy:415)
        at gant.Gant$_dispatch_closure7.doCall(Gant.groovy)
        at gant.Gant.withBuildListeners(Gant.groovy:427)
        at gant.Gant.this$2$withBuildListeners(Gant.groovy)
        at gant.Gant$this$2$withBuildListeners.callCurrent(Unknown Source)
        at gant.Gant.dispatch(Gant.groovy:415)
        at gant.Gant.this$2$dispatch(Gant.groovy)
        at gant.Gant.invokeMethod(Gant.groovy)
        at gant.Gant.executeTargets(Gant.groovy:590)
        at gant.Gant.executeTargets(Gant.groovy:589)
Caused by: java.lang.NoClassDefFoundError: org/hibernate/MappingException
        ... 15 more
Caused by: java.lang.ClassNotFoundException: org.hibernate.MappingException
        at org.codehaus.groovy.tools.RootLoader.findClass(RootLoader.java:156)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at org.codehaus.groovy.tools.RootLoader.loadClass(RootLoader.java:128)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
        ... 15 more
Error running generate-all: null

What am I doing wrong?

Where is the log file that I’m supposed to consult for details?

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1 Answer

  1. Editorial Team

    It seems that setting visibility to false with the standard scaffolding causes errors. I had to delete the middle line from this block, and it worked:

     static constraints = {
   id visible:false
 }

    I suppose this is one of the costs of ‘convention over configuration’: hidden dependencies. Or it could be that I’m still learning…

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