Fails on custom jdk1.8.0b120(link in comment) and jdk1.8.0b119. Fails on jdk1.7.0_45b18 for another reason. So it can be regression.

on jdk1.8.0 fails with exception

java.lang.Error: the child property type is not override the parent property type
at Test8027648.test(Test8027648.java:45)
at Test8027648.main(Test8027648.java:38)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at com.sun.javatest.regtest.MainWrapper$MainThread.run(MainWrapper.java:94)
at java.lang.Thread.run(Thread.java:744)

on jdk1.7.0_45b18 with

java.lang.AssertionError: java.beans.IntrospectionException: type mismatch between indexed read and indexed write methods: index
        at java.beans.IndexedPropertyDescriptor.<init>(IndexedPropertyDescriptor.java:480)
        at java.beans.Introspector.processPropertyDescriptors(Introspector.java:647)
        at java.beans.Introspector.getTargetPropertyInfo(Introspector.java:543)
        at java.beans.Introspector.getBeanInfo(Introspector.java:418)
        at java.beans.Introspector.getBeanInfo(Introspector.java:163)
        at BeanUtils.getPropertyDescriptors(BeanUtils.java:64)
        at BeanUtils.findPropertyDescriptor(BeanUtils.java:111)
        at Test8027648.getPropertyType(Test8027648.java:50)
        at Test8027648.test(Test8027648.java:43)
        at Test8027648.main(Test8027648.java:37)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at com.sun.javatest.regtest.MainWrapper$MainThread.run(MainWrapper.java:94)
        at java.lang.Thread.run(Thread.java:744)
Caused by: java.beans.IntrospectionException: type mismatch between indexed read and indexed write methods: index
        at java.beans.IndexedPropertyDescriptor.findIndexedPropertyType(IndexedPropertyDescriptor.java:387)
        at java.beans.IndexedPropertyDescriptor.setIndexedReadMethod(IndexedPropertyDescriptor.java:215)
        at java.beans.IndexedPropertyDescriptor.<init>(IndexedPropertyDescriptor.java:471)
        ... 15 more