Unable to create a new UI mockup in AOD Confluence space comment

Steps to reproduce

• Create an Confluence Space
• In the Write Comment Box, add a "Mockup macro" BUT do not click on the macro
• Save the changes
• Click on "Click here to create a new UI mockup"

Below is the error message you should be facing:

Cause
java.lang.ClassCastException: com.atlassian.confluence.pages.Comment cannot be cast to com.atlassian.confluence.pages.AbstractPage
at com.atlassian.confluence.pages.persistence.dao.hibernate.HibernateAbstractPageDao.getAbstractPageById(HibernateAbstractPageDao.java:18)

Stack Trace:[hide]
java.lang.ClassCastException: com.atlassian.confluence.pages.Comment cannot be cast to com.atlassian.confluence.pages.AbstractPage
at com.atlassian.confluence.pages.persistence.dao.hibernate.HibernateAbstractPageDao.getAbstractPageById(HibernateAbstractPageDao.java:18)
at sun.reflect.GeneratedMethodAccessor741.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy43.getAbstractPageById(Unknown Source)
at com.atlassian.confluence.pages.DefaultPageManager.getAbstractPage(DefaultPageManager.java:140)
at com.atlassian.confluence.pages.DefaultPageManager.getById(DefaultPageManager.java:151)
at sun.reflect.GeneratedMethodAccessor1129.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at com.atlassian.spring.interceptors.SpringProfilingInterceptor.invoke(SpringProfilingInterceptor.java:16)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
at $Proxy45.getById(Unknown Source)
at com.balsamiq.confluence.plugins.mockups.MockupsServlet.service(MockupsServlet.java:109)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at com.atlassian.plugin.servlet.DelegatingPluginServlet.service(DelegatingPluginServlet.java:42)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at com.atlassian.plugin.servlet.ServletModuleContainerServlet.service(ServletModuleContainerServlet.java:52)