我正在运行一个启用了g1gc的java应用程序，并打印gc日志，如下所示：

[4074.182s][info][gc] GC(1017) Pause Young (Normal) (G1 Evacuation Pause) 6869M->6115M(16384M) 7430.860ms
[4082.328s][info][gc] GC(1018) Pause Young (Normal) (G1 Evacuation Pause) 6875M->6121M(16384M) 7058.485ms
[4089.592s][info][gc] GC(1019) Pause Young (Normal) (G1 Evacuation Pause) 6881M->6126M(16384M) 6172.693ms
[4105.799s][info][gc] GC(1021) Pause Young (Normal) (G1 Evacuation Pause) 6892M->6137M(16384M) 6845.922ms
[4114.418s][info][gc] GC(1022) Pause Young (Normal) (G1 Evacuation Pause) 6897M->6142M(16384M) 7563.613ms
[4122.805s][info][gc] GC(1023) Pause Young (Normal) (G1 Evacuation Pause) 6902M->6148M(16384M) 7326.923ms
[4131.270s][info][gc] GC(1024) Pause Young (Normal) (G1 Evacuation Pause) 6908M->6155M(16384M) 7402.222ms
[4140.574s][info][gc] GC(1025) Pause Young (Normal) (G1 Evacuation Pause) 6915M->6161M(16384M) 8226.283ms
[4149.429s][info][gc] GC(1026) Pause Young (Normal) (G1 Evacuation Pause) 6921M->6167M(16384M) 7779.282ms
[4157.078s][info][gc] GC(1027) Pause Young (Normal) (G1 Evacuation Pause) 6927M->6172M(16384M) 6559.166ms

我对这个日志的理解是：

[4074.182s][info][gc] GC(1017) Pause Young (Normal) (G1 Evacuation Pause) 6869M->6115M(16384M) 7430.860ms

As per my understanding this shows that 4074.182 seconds after application started, a young generation 
Stop the world gc was kicked in, and heap size before gc heap size was 6869M 
and after gc it reduced to 6115M and it took 7430.860ms (more than 7 seconds).

我的问题：

1. Is this young gc stopping all the application threads ?
2. If it is stopping all the application threads then looks like application is not 
   running at all during all these gc logs were printed because:
    after [4074.182s] young gc kicked in and it took aroung 7.5 seconds (7430.860ms)
    after ~8 seconds, [4082.328s] yound gc kicked in again and took around 7 seonds and so on.
   So it looks like application is not getting any free slot here to run ?