The hs_err file only lists the Java threads, the VM thread, and Watcher thread, not the various gc threads.

It should say something like:

--------------- P R O C E S S ---------------

Java Threads: ( => current thread )
  0x00007f77b8586000 JavaThread "Service Thread" daemon [_thread_blocked, id=25893, stack(0x00007f77026cc000,0x00007f77027cd000)]
  0x00007f77b83fb000 JavaThread "Sweeper thread" daemon [_thread_blocked, id=25892, stack(0x00007f7702bf4000,0x00007f7702cf5000)]
  0x00007f77b83f8800 JavaThread "C1 CompilerThread11" daemon [_thread_blocked, id=25891, stack(0x00007f7702cf5000,0x00007f7702df6000)]
  0x00007f77b83f6000 JavaThread "C1 CompilerThread10" daemon [_thread_in_native, id=25890, stack(0x00007f7702df6000,0x00007f7702ef7000)]
  0x00007f77b83f3800 JavaThread "C1 CompilerThread9" daemon [_thread_blocked, id=25889, stack(0x00007f7702ef7000,0x00007f7702ff8000)]
  0x00007f77b83f1000 JavaThread "C1 CompilerThread8" daemon [_thread_blocked, id=25888, stack(0x00007f7702ff8000,0x00007f77030f9000)]
  0x00007f77b83ee800 JavaThread "C2 CompilerThread7" daemon [_thread_in_native, id=25887, stack(0x00007f77030f9000,0x00007f77031fa000)]
  0x00007f77b83ec000 JavaThread "C2 CompilerThread6" daemon [_thread_in_native, id=25886, stack(0x00007f77031fa000,0x00007f77032fb000)]
  0x00007f77b83e9800 JavaThread "C2 CompilerThread5" daemon [_thread_blocked, id=25885, stack(0x00007f77032fb000,0x00007f77033fc000)]
  0x00007f77b83e7000 JavaThread "C2 CompilerThread4" daemon [_thread_blocked, id=25884, stack(0x00007f77033fc000,0x00007f77034fd000)]
  0x00007f77b83dc800 JavaThread "C2 CompilerThread3" daemon [_thread_in_native, id=25883, stack(0x00007f77034fd000,0x00007f77035fe000)]
  0x00007f77b83da000 JavaThread "C2 CompilerThread2" daemon [_thread_blocked, id=25882, stack(0x00007f77035fe000,0x00007f77036ff000)]
  0x00007f77b83d7800 JavaThread "C2 CompilerThread1" daemon [_thread_in_native, id=25881, stack(0x00007f77036ff000,0x00007f7703800000)]
  0x00007f77b83d5000 JavaThread "C2 CompilerThread0" daemon [_thread_blocked, id=25880, stack(0x00007f770c066000,0x00007f770c167000)]
  0x00007f77b83d2000 JavaThread "Signal Dispatcher" daemon [_thread_blocked, id=25879, stack(0x00007f770c167000,0x00007f770c268000)]
  0x00007f77b83d0000 JavaThread "Reference Pending List Locker" daemon [_thread_blocked, id=25878, stack(0x00007f770c268000,0x00007f770c36900
0)]
  0x00007f77b839b000 JavaThread "Finalizer" daemon [_thread_blocked, id=25877, stack(0x00007f770c369000,0x00007f770c46a000)]
  0x00007f77b8399000 JavaThread "Reference Handler" daemon [_thread_blocked, id=25876, stack(0x00007f770c46a000,0x00007f770c56b000)]
=>0x00007f77b8017000 JavaThread "main" [_thread_in_vm, id=25835, stack(0x00007f77bee07000,0x00007f77bef08000)]

Other Threads:
  0x00007f77b8384800 VMThread "VM Thread" [stack: 0x00007f770c56b000,0x00007f770c66c000] [id=25875]
  0x00007f77b8589800 WatcherThread [stack: 0x00007f77025cb000,0x00007f77026cc000] [id=25894]
  0x00007f77b8035000 GCTaskThread "GC Thread#0" [stack: 0x00007f779f50b000,0x00007f779f60c000] [id=25837]
  0x00007f77b8037000 GCTaskThread "GC Thread#1" [stack: 0x00007f779f40a000,0x00007f779f50b000] [id=25838]
  0x00007f77b8039000 GCTaskThread "GC Thread#2" [stack: 0x00007f779f309000,0x00007f779f40a000] [id=25839]
  0x00007f77b803b000 GCTaskThread "GC Thread#3" [stack: 0x00007f779f208000,0x00007f779f309000] [id=25840]
  0x00007f77b803d000 GCTaskThread "GC Thread#4" [stack: 0x00007f779f107000,0x00007f779f208000] [id=25841]
  0x00007f77b803f000 GCTaskThread "GC Thread#5" [stack: 0x00007f779f006000,0x00007f779f107000] [id=25842]
  0x00007f77b8041000 GCTaskThread "GC Thread#6" [stack: 0x00007f779ef05000,0x00007f779f006000] [id=25843]
  0x00007f77b8043000 GCTaskThread "GC Thread#7" [stack: 0x00007f779ee04000,0x00007f779ef05000] [id=25844]
  0x00007f77b8045000 GCTaskThread "GC Thread#8" [stack: 0x00007f779ed03000,0x00007f779ee04000] [id=25845]
  0x00007f77b8047000 GCTaskThread "GC Thread#9" [stack: 0x00007f779ec02000,0x00007f779ed03000] [id=25846]
  0x00007f77b8049000 GCTaskThread "GC Thread#10" [stack: 0x00007f779eb01000,0x00007f779ec02000] [id=25847]
  0x00007f77b804b000 GCTaskThread "GC Thread#11" [stack: 0x00007f779ea00000,0x00007f779eb01000] [id=25848]
  0x00007f77b804d800 GCTaskThread "GC Thread#12" [stack: 0x00007f779e8ff000,0x00007f779ea00000] [id=25849]
  0x00007f77b807e800 ConcurrentGCThread "G1 Main Marker" [stack: 0x00007f779ca7d000,0x00007f779cb7e000] [id=25865]
  0x00007f77b8081000 ConcurrentGCThread "G1 Marker#0" [stack: 0x00007f779c97c000,0x00007f779ca7d000] [id=25866]
  0x00007f77b8083000 ConcurrentGCThread "G1 Marker#1" [stack: 0x00007f779c87b000,0x00007f779c97c000] [id=25867]
  0x00007f77b8085000 ConcurrentGCThread "G1 Marker#2" [stack: 0x00007f779c77a000,0x00007f779c87b000] [id=25868]
  0x00007f77b806a000 ConcurrentGCThread "G1 Refine#0" [stack: 0x00007f779cee5000,0x00007f779cfe6000] [id=25863]
  0x00007f77b8068000 ConcurrentGCThread "G1 Refine#1" [stack: 0x00007f779cfe6000,0x00007f779d0e7000] [id=25862]
  0x00007f77b8065800 ConcurrentGCThread "G1 Refine#2" [stack: 0x00007f779d0e7000,0x00007f779d1e8000] [id=25861]
  0x00007f77b8063800 ConcurrentGCThread "G1 Refine#3" [stack: 0x00007f779d1e8000,0x00007f779d2e9000] [id=25860]
  0x00007f77b8061800 ConcurrentGCThread "G1 Refine#4" [stack: 0x00007f779d2e9000,0x00007f779d3ea000] [id=25859]
  0x00007f77b805f800 ConcurrentGCThread "G1 Refine#5" [stack: 0x00007f779d3ea000,0x00007f779d4eb000] [id=25858]
  0x00007f77b805d000 ConcurrentGCThread "G1 Refine#6" [stack: 0x00007f779d4eb000,0x00007f779d5ec000] [id=25857]
  0x00007f77b805b000 ConcurrentGCThread "G1 Refine#7" [stack: 0x00007f779d5ec000,0x00007f779d6ed000] [id=25856]
  0x00007f77b8059000 ConcurrentGCThread "G1 Refine#8" [stack: 0x00007f779d6ed000,0x00007f779d7ee000] [id=25855]
  0x00007f77b8057000 ConcurrentGCThread "G1 Refine#9" [stack: 0x00007f779d7ee000,0x00007f779d8ef000] [id=25854]
  0x00007f77b8055000 ConcurrentGCThread "G1 Refine#10" [stack: 0x00007f779d8ef000,0x00007f779d9f0000] [id=25853]
  0x00007f77b8052800 ConcurrentGCThread "G1 Refine#11" [stack: 0x00007f779d9f0000,0x00007f779daf1000] [id=25852]
  0x00007f77b8050800 ConcurrentGCThread "G1 Refine#12" [stack: 0x00007f779daf1000,0x00007f779dbf2000] [id=25851]
  0x00007f77b806c000 ConcurrentGCThread "G1 Young RemSet Sampling" [stack: 0x00007f779cde4000,0x00007f779cee5000] [id=25864]
  0x00007f77b8296000 ConcurrentGCThread "G1 StrDedup" [stack: 0x00007f770c757000,0x00007f770c858000] [id=25871]