String index out of range: Exception when executing scaffolding process in Roo GWT for a "set" field

java.lang.StringIndexOutOfBoundsException: String index out of range: -1
   at java.lang.String.substring(String.java:1937)
   at org.springframework.roo.addon.gwt.GwtTemplateServiceImpl.buildMirrorDataDictionary(GwtTemplateServiceImpl.java:576)
   at org.springframework.roo.addon.gwt.GwtTemplateServiceImpl.getMirrorTemplateTypeDetails(GwtTemplateServiceImpl.java:111)
   at org.springframework.roo.addon.gwt.scaffold.GwtScaffoldMetadataProviderImpl.get(GwtScaffoldMetadataProviderImpl.java:139)
   at org.springframework.roo.metadata.DefaultMetadataService.getInternal(DefaultMetadataService.java:150)
   at org.springframework.roo.metadata.DefaultMetadataService.evictAndGet(DefaultMetadataService.java:285)
   at org.springframework.roo.addon.gwt.scaffold.GwtScaffoldMetadataProviderImpl.notify(GwtScaffoldMetadataProviderImpl.java:236)
   at org.springframework.roo.metadata.DefaultMetadataService.notify(DefaultMetadataService.java:240)
   at org.springframework.roo.metadata.internal.DefaultMetadataDependencyRegistry.notifyDownstream(DefaultMetadataDependencyRegistry.java:214)
   at org.springframework.roo.classpath.DefaultPhysicalTypeMetadataProvider.onFileEvent(DefaultPhysicalTypeMetadataProvider.java:97)
   at org.springframework.roo.file.monitor.polling.PollingFileMonitorService.publish(PollingFileMonitorService.java:352)
   at org.springframework.roo.file.monitor.polling.PollingFileMonitorService.scanAll(PollingFileMonitorService.java:325)
   at org.springframework.roo.process.manager.internal.DefaultProcessManager.doTransactionally(DefaultProcessManager.java:181)
   at org.springframework.roo.process.manager.internal.DefaultProcessManager.backgroundPoll(DefaultProcessManager.java:128)
   at org.springframework.roo.process.manager.internal.DefaultProcessManager.timerBasedPoll(DefaultProcessManager.java:243)
   at org.springframework.roo.process.manager.internal.DefaultProcessManager$2.run(DefaultProcessManager.java:71)
   at java.lang.Thread.run(Thread.java:680)

project --topLevelPackage com.foo.roo2881
jpa setup --provider ECLIPSELINK --database H2_IN_MEMORY

entity jpa --class ~.domain.foo1 --testAutomatically

entity jpa --class ~.domain.foo2 --testAutomatically
field set --fieldName bar --type foo1

web gwt setup
web gwt all --proxyPackage ~.client.proxy --requestPackage ~.client.request