Fix the errors reported by the Javadoc tool in JDK8

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:2.9:javadoc (default-cli) on project oak-core: An error has occurred in JavaDocs report generation:
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\blob\AbstractSharedCachingDataStore.java:66: error: bad use of '>'
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\blob\AbstractSharedCachingDataStore.java:68: error: bad use of '>'
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\blob\AbstractSharedCachingDataStore.java:69: error: bad use of '>'
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\blob\AbstractSharedCachingDataStore.java:70: error: bad use of '>'
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\blob\AbstractSharedCachingDataStore.java:71: error: bad use of '>'
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\blob\AbstractSharedCachingDataStore.java:72: error: bad use of '>'
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\blob\AbstractSharedCachingDataStore.java:73: error: bad use of '>'
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\blob\AbstractSharedCachingDataStore.java:74: error: bad use of '>'
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\blob\AbstractSharedCachingDataStore.java:65: error: element not closed: pre
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\blob\UploadStagingCache.java:465: error: reference not found
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\document\AbstractDocumentNodeState.java:50: error: reference not found
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\document\AbstractDocumentNodeState.java:52: error: reference not found
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\document\AbstractDocumentNodeState.java:56: error: reference not found
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\multiplex\MultiplexingNodeStore.java:67: error: unexpected end tag: </p>
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\observation\FilteringObserver.java:71: error: bad use of '>'
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\observation\FilteringObserver.java:71: error: bad use of '>'
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\multiplex\package-info.java:31: error: unexpected end tag: </p>
[ERROR] C:\projects\apache\oak\trunk\oak-core\src\main\java\org\apache\jackrabbit\oak\plugins\multiplex\package-info.java:58: error: unexpected end tag: </p>