In the meanwhile I got an idea to look into driver log. I've found this:

2016-08-04T19:19:57.980+0000: [GC (Allocation Failure) [PSYoungGen: 6827008K->52511K(7299584K)] 7660819K->886330K(22848000K), 0.0142959 secs] [Times: user=0.08 sys=0.01, real=0.01 secs]

...

04T19:27:03.294+0000: [GC (Allocation Failure) [PSYoungGen: 7270001K->134234K(7454208K)] 8103861K->968093K(23002624K), 0.0509207 secs] [Times: user=0.33 sys=0.00, real=0.05 secs]