Coverity static analysis: DefaultSingleSignOn.getIdentity() not synchronized

Coverity static-analysis scan found getter is not synchronized, while setter is.

public SecurityIdentity getIdentity() {
    return this.entry.getCachedIdentity().getSecurityIdentity();
}

Current implementation is correct because in DefaultSingleSignOnEntry (currently only avalaible implementation of SingleSignOnEntry) cachedIdentity is volatile.

However other implementations can be wrongly implemented. Once getIdentity() would be marked with synchronize modifier, such problem shouldn't occure.

https://scan7.coverity.com/reports.htm#v23632/p11778/fileInstanceId=8490896&defectInstanceId=2123245&mergedDefectId=1396940