The output from -XX:+PrintHeapAtGC is useful for diagnosing problems with GC. However,
it interferes with any tool that tries to scan stdout for output from a java application,
including refworkload and alacrity. The current PrintHeapAtGC output looks like this
(line numbers added):

 1: {Heap before GC invocations=1:
 2:Heap
 3: PSYoungGen total 3584K, used 3072K [0xf2400000, 0xf2800000, 0xf7000000)
 4: ... elided ...
 5:0.000: [GC [PSYoungGen: 3072K->280K(3584K)] 3072K->280K(7680K), 0.0355146 secs]
 6: Heap after GC invocations=1:
 7:Heap
 8: PSYoungGen total 3584K, used 280K [0xf2400000, 0xf2800000, 0xf7000000)
 9: ... elided ...
10:} {Heap before GC invocations=2:
11:Heap
12: PSYoungGen total 3584K, used 3352K [0xf2400000, 0xf2800000, 0xf7000000)
13: ...

The primary problem is that the closing brace on line 10 isn't followed by a newline.