Cannot enable Team Calendars plugin once installed in some older minor revisions of Confluence 3.5

Steps to reproduce

1. Install Team Calendar plugin in Confluence 3.5
2. The plugin will be installed, but disabled. You won't be able to enable the plugin. The following will be thrown in the log:

   2011-06-08 03:55:06,452 ERROR [Spring executor 15] [plugin.osgi.factory.OsgiPlugin] onSpringContextFailed Unable to start the Spring context for plugin com.atlassian.confluence.extra.team-calendars
    -- referer: http://localhost:8035/plugins/servlet/upm | url: /rest/plugins/1.0/ | userName: admin
   org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'calendarRenderer' defined in URL [bundle://71.0:0/META-INF/spring/spring-components.xml]: Cannot resolve reference to bean 'licenseAccessor' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'licenseAccessor' defined in URL [bundle://71.0:0/META-INF/spring/spring-components.xml]: Invocation of init method failed; nested exception is java.lang.NoSuchMethodError: com.atlassian.confluence.user.UserAccessor.countUsersWithConfluenceAccess()I
   	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:275)
   	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:104)
   	at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:495)
   	at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:162)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:925)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:835)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:440)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409)
   	at java.security.AccessController.doPrivileged(Native Method)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380)
   	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264)
   	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
   	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261)
   	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185)
   	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)
   	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:429)
   	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:728)
   	at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext.access$1600(AbstractDelegatedExecutionApplicationContext.java:69)
   	at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext$4.run(AbstractDelegatedExecutionApplicationContext.java:355)
   	at org.springframework.osgi.util.internal.PrivilegedUtils.executeWithCustomTCCL(PrivilegedUtils.java:85)
   	at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext.completeRefresh(AbstractDelegatedExecutionApplicationContext.java:320)
   	at org.springframework.osgi.extender.internal.dependencies.startup.DependencyWaiterApplicationContextExecutor$CompleteRefreshTask.run(DependencyWaiterApplicationContextExecutor.java:132)
   	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
   	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
   	at java.lang.Thread.run(Thread.java:662)
   Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'licenseAccessor' defined in URL [bundle://71.0:0/META-INF/spring/spring-components.xml]: Invocation of init method failed; nested exception is java.lang.NoSuchMethodError: com.atlassian.confluence.user.UserAccessor.countUsersWithConfluenceAccess()I
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1338)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:473)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409)
   	at java.security.AccessController.doPrivileged(Native Method)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380)
   	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264)
   	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
   	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261)
   	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185)
   	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)
   	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:269)
   	... 24 more
   Caused by: java.lang.NoSuchMethodError: com.atlassian.confluence.user.UserAccessor.countUsersWithConfluenceAccess()I
   	at com.atlassian.confluence.extra.calendar3.license.LicenseAccessor.afterPropertiesSet(LicenseAccessor.java:96)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1369)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1335)
   	... 34 more
   2011-06-08 03:55:06,454 ERROR [Spring executor 15] [extender.internal.activator.ContextLoaderListener] onOsgiApplicationEvent Application context refresh failed (NonValidatingOsgiBundleXmlApplicationContext(bundle=com.atlassian.confluence.extra.team-calendars, config=osgibundle:/META-INF/spring/*.xml))
    -- referer: http://localhost:8035/plugins/servlet/upm | url: /rest/plugins/1.0/ | userName: admin
   org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'calendarRenderer' defined in URL [bundle://71.0:0/META-INF/spring/spring-components.xml]: Cannot resolve reference to bean 'licenseAccessor' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'licenseAccessor' defined in URL [bundle://71.0:0/META-INF/spring/spring-components.xml]: Invocation of init method failed; nested exception is java.lang.NoSuchMethodError: com.atlassian.confluence.user.UserAccessor.countUsersWithConfluenceAccess()I
   	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:275)
   	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:104)
   	at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:495)
   	at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:162)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:925)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:835)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:440)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409)
   	at java.security.AccessController.doPrivileged(Native Method)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380)
   	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264)
   	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
   	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261)
   	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185)
   	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)
   	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:429)
   	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:728)
   	at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext.access$1600(AbstractDelegatedExecutionApplicationContext.java:69)
   	at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext$4.run(AbstractDelegatedExecutionApplicationContext.java:355)
   	at org.springframework.osgi.util.internal.PrivilegedUtils.executeWithCustomTCCL(PrivilegedUtils.java:85)
   	at org.springframework.osgi.context.support.AbstractDelegatedExecutionApplicationContext.completeRefresh(AbstractDelegatedExecutionApplicationContext.java:320)
   	at org.springframework.osgi.extender.internal.dependencies.startup.DependencyWaiterApplicationContextExecutor$CompleteRefreshTask.run(DependencyWaiterApplicationContextExecutor.java:132)
   	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
   	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
   	at java.lang.Thread.run(Thread.java:662)
   Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'licenseAccessor' defined in URL [bundle://71.0:0/META-INF/spring/spring-components.xml]: Invocation of init method failed; nested exception is java.lang.NoSuchMethodError: com.atlassian.confluence.user.UserAccessor.countUsersWithConfluenceAccess()I
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1338)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:473)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409)
   	at java.security.AccessController.doPrivileged(Native Method)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:380)
   	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:264)
   	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
   	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:261)
   	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:185)
   	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:164)
   	at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:269)
   	... 24 more
   Caused by: java.lang.NoSuchMethodError: com.atlassian.confluence.user.UserAccessor.countUsersWithConfluenceAccess()I
   	at com.atlassian.confluence.extra.calendar3.license.LicenseAccessor.afterPropertiesSet(LicenseAccessor.java:96)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1369)
   	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1335)
   	... 34 more
   

Finding

The plugin can be installed and enabled flawlessly in Confluence 3.5.2 onwards.

Workaround

Upgrade to Confluence 3.5.2 or higher in the meantime.