怎么看我当前运行的是哪个垃圾收集器

1 -XX:+UseSerialGC  serial/serial old

0.222: [Full GC (System.gc()) 0.222: [Tenured: 0K->16898K(102400K), 0.0164019 secs] 21299K->16898K(194560K), [Metaspace: 2458K->2458K(1056768K)], 0.0165361 secs] [Times: user=0.00 sys=0.02, real=0.02 secs]
Heap
 def new generation   total 92160K, used 2458K [0x00000000f3800000, 0x00000000f9c00000, 0x00000000f9c00000)
  eden space 81920K,   3% used [0x00000000f3800000, 0x00000000f3a66840, 0x00000000f8800000)
  from space 10240K,   0% used [0x00000000f8800000, 0x00000000f8800000, 0x00000000f9200000)
  to   space 10240K,   0% used [0x00000000f9200000, 0x00000000f9200000, 0x00000000f9c00000)
 tenured generation   total 102400K, used 16898K [0x00000000f9c00000, 0x0000000100000000, 0x0000000100000000)
   the space 102400K,  16% used [0x00000000f9c00000, 0x00000000fac80b60, 0x00000000fac80c00, 0x0000000100000000)
 Metaspace       used 2467K, capacity 4486K, committed 4864K, reserved 1056768K
  class space    used 272K, capacity 386K, committed 512K, reserved 1048576K

2 -XX:+UseParNewGC parNew/serial old

0.148: [Full GC (System.gc()) 0.148: [Tenured: 0K->16898K(102400K), 0.0235919 secs] 21299K->16898K(194560K), [Metaspace: 2458K->2458K(1056768K)], 0.0237012 secs] [Times: user=0.00 sys=0.02, real=0.02 secs]
Heap
 par new generation   total 92160K, used 2458K [0x00000000f3800000, 0x00000000f9c00000, 0x00000000f9c00000)
  eden space 81920K,   3% used [0x00000000f3800000, 0x00000000f3a66840, 0x00000000f8800000)
  from space 10240K,   0% used [0x00000000f8800000, 0x00000000f8800000, 0x00000000f9200000)
  to   space 10240K,   0% used [0x00000000f9200000, 0x00000000f9200000, 0x00000000f9c00000)
 tenured generation   total 102400K, used 16898K [0x00000000f9c00000, 0x0000000100000000, 0x0000000100000000)
   the space 102400K,  16% used [0x00000000f9c00000, 0x00000000fac80b60, 0x00000000fac80c00, 0x0000000100000000)
 Metaspace       used 2467K, capacity 4486K, committed 4864K, reserved 1056768K
  class space    used 272K, capacity 386K, committed 512K, reserved 1048576K
Java HotSpot(TM) 64-Bit Server VM warning: Using the ParNew young collector with the Serial old collector is deprecated and will likely be removed in a future release

3 -XX:+UseConcMarkSweepGC  parNew/CMS

0.195: [Full GC (System.gc()) 0.195: [CMS: 0K->16902K(102400K), 0.0305387 secs] 19661K->16902K(194560K), [Metaspace: 2455K->2455K(1056768K)], 0.0306686 secs] [Times: user=0.00 sys=0.02, real=0.03 secs]
Heap
 par new generation   total 92160K, used 2458K [0x00000000f3800000, 0x00000000f9c00000, 0x00000000f9c00000)
  eden space 81920K,   3% used [0x00000000f3800000, 0x00000000f3a66840, 0x00000000f8800000)
  from space 10240K,   0% used [0x00000000f8800000, 0x00000000f8800000, 0x00000000f9200000)
  to   space 10240K,   0% used [0x00000000f9200000, 0x00000000f9200000, 0x00000000f9c00000)
 concurrent mark-sweep generation total 102400K, used 16902K [0x00000000f9c00000, 0x0000000100000000, 0x0000000100000000)
 Metaspace       used 2464K, capacity 4486K, committed 4864K, reserved 1056768K
  class space    used 272K, capacity 386K, committed 512K, reserved 1048576K

4 -XX:+UseParallelGC  parallel Scavenge/parallel old

0.140: [GC (System.gc()) [PSYoungGen: 20992K->8792K(89600K)] 20992K->16992K(192000K), 0.0468877 secs] [Times: user=0.06 sys=0.00, real=0.05 secs]
0.187: [Full GC (System.gc()) [PSYoungGen: 8792K->0K(89600K)] [ParOldGen: 8200K->16898K(102400K)] 16992K->16898K(192000K), [Metaspace: 2458K->2458K(1056768K)], 0.0420516 secs] [Times: user=0.05 sys=0.03, real=0.05 secs]
Heap
 PSYoungGen      total 89600K, used 2304K [0x00000000f9c00000, 0x0000000100000000, 0x0000000100000000)
  eden space 76800K, 3% used [0x00000000f9c00000,0x00000000f9e401e0,0x00000000fe700000)
  from space 12800K, 0% used [0x00000000fe700000,0x00000000fe700000,0x00000000ff380000)
  to   space 12800K, 0% used [0x00000000ff380000,0x00000000ff380000,0x0000000100000000)
 ParOldGen       total 102400K, used 16898K [0x00000000f3800000, 0x00000000f9c00000, 0x00000000f9c00000)
  object space 102400K, 16% used [0x00000000f3800000,0x00000000f4880b60,0x00000000f9c00000)
 Metaspace       used 2467K, capacity 4486K, committed 4864K, reserved 1056768K
  class space    used 272K, capacity 386K, committed 512K, reserved 1048576K

5 -XX:+UseParallelOldGC  parallel Scavenge/parallel old

0.155: [GC (System.gc()) [PSYoungGen: 19456K->8792K(89600K)] 19456K->16992K(192000K), 0.0239985 secs] [Times: user=0.06 sys=0.03, real=0.03 secs]
0.179: [Full GC (System.gc()) [PSYoungGen: 8792K->0K(89600K)] [ParOldGen: 8200K->16898K(102400K)] 16992K->16898K(192000K), [Metaspace: 2455K->2455K(1056768K)], 0.0147495 secs] [Times: user=0.02 sys=0.02, real=0.02 secs]
Heap
 PSYoungGen      total 89600K, used 2304K [0x00000000f9c00000, 0x0000000100000000, 0x0000000100000000)
  eden space 76800K, 3% used [0x00000000f9c00000,0x00000000f9e401e0,0x00000000fe700000)
  from space 12800K, 0% used [0x00000000fe700000,0x00000000fe700000,0x00000000ff380000)
  to   space 12800K, 0% used [0x00000000ff380000,0x00000000ff380000,0x0000000100000000)
 ParOldGen       total 102400K, used 16898K [0x00000000f3800000, 0x00000000f9c00000, 0x00000000f9c00000)
  object space 102400K, 16% used [0x00000000f3800000,0x00000000f4880b30,0x00000000f9c00000)
 Metaspace       used 2464K, capacity 4486K, committed 4864K, reserved 1056768K
  class space    used 272K, capacity 386K, committed 512K, reserved 1048576K

 

6 -XX:+UseG1GC

0.172: [Full GC (System.gc())  17M->16M(200M), 0.0110886 secs]
   [Eden: 2048.0K(100.0M)->0.0B(100.0M) Survivors: 0.0B->0.0B Heap: 17.5M(200.0M)->16.5M(200.0M)], [Metaspace: 2456K->2456K(1056768K)]
 [Times: user=0.00 sys=0.02, real=0.01 secs]
Heap
 garbage-first heap   total 204800K, used 16899K [0x00000000f3800000, 0x0000000100000000, 0x0000000100000000)
  region size 1024K, 1 young (1024K), 0 survivors (0K)
 Metaspace       used 2465K, capacity 4486K, committed 4864K, reserved 1056768K
  class space    used 272K, capacity 386K, committed 512K, reserved 1048576K