The conversion to Unified Logging framework left an unmatched ']' at the end of G1's string deduplication printouts.
Like this:
[13.742s][info][gc,stringdedup] Concurrent String Deduplication 168.9M->168.9M(31.3K), avg 0.0%, 8.6307965 secs]
Like this:
[13.742s][info][gc,stringdedup] Concurrent String Deduplication 168.9M->168.9M(31.3K), avg 0.0%, 8.6307965 secs]