package org.ziegler.gc;/*** VM参数：-XX:+UseG1GC -Xms20M -Xmx20M -Xmn10M -Xlog:gc* -XX:SurvivorRatio=8* */
public class FirstTestGC {public static void main(String[] args) {byte[] a1, a2, a3, a4;a1 = new byte[2 * 1024 * 1024];a2 = new byte[2 * 1024 * 1024];a3 = new byte[2 * 1024 * 1024];a4 = new byte[4 * 1024 * 1024];final int i = a1[0] + a2[0] + a3[0] + a4[0];System.out.println(i);}
}

[0.023s][info][gc,heap] Heap region size: 1M
[0.025s][info][gc     ] Using G1
[0.025s][info][gc,heap,coops] Heap address: 0x00000000fec00000, size: 20 MB, Compressed Oops mode: 32-bit
[0.260s][info][gc,start     ] GC(0) Pause Young (Concurrent Start) (G1 Humongous Allocation)
[0.260s][info][gc,task      ] GC(0) Using 2 workers of 8 for evacuation
[0.263s][info][gc,phases    ] GC(0)   Pre Evacuate Collection Set: 0.0ms
[0.263s][info][gc,phases    ] GC(0)   Evacuate Collection Set: 2.8ms
[0.263s][info][gc,phases    ] GC(0)   Post Evacuate Collection Set: 0.1ms
[0.263s][info][gc,phases    ] GC(0)   Other: 0.3ms
[0.263s][info][gc,heap      ] GC(0) Eden regions: 3->0(8)
[0.263s][info][gc,heap      ] GC(0) Survivor regions: 0->2(2)
[0.263s][info][gc,heap      ] GC(0) Old regions: 0->0
[0.263s][info][gc,heap      ] GC(0) Humongous regions: 9->9
[0.263s][info][gc,metaspace ] GC(0) Metaspace: 6310K->6310K(1056768K)
[0.263s][info][gc           ] GC(0) Pause Young (Concurrent Start) (G1 Humongous Allocation) 11M->10M(20M) 3.375ms
[0.263s][info][gc,cpu       ] GC(0) User=0.00s Sys=0.00s Real=0.00s
[0.263s][info][gc           ] GC(1) Concurrent Cycle
[0.263s][info][gc,marking   ] GC(1) Concurrent Clear Claimed Marks
[0.263s][info][gc,marking   ] GC(1) Concurrent Clear Claimed Marks 0.010ms
[0.263s][info][gc,marking   ] GC(1) Concurrent Scan Root Regions
[0.264s][info][gc,marking   ] GC(1) Concurrent Scan Root Regions 0.887ms
[0.264s][info][gc,marking   ] GC(1) Concurrent Mark (0.264s)
[0.264s][info][gc,marking   ] GC(1) Concurrent Mark From Roots
[0.264s][info][gc,task      ] GC(1) Using 2 workers of 2 for marking
0
[0.272s][info][gc,marking   ] GC(1) Concurrent Mark From Roots 7.998ms
[0.272s][info][gc,marking   ] GC(1) Concurrent Preclean
[0.272s][info][gc,marking   ] GC(1) Concurrent Preclean 0.139ms
[0.272s][info][gc,marking   ] GC(1) Concurrent Mark (0.264s, 0.272s) 8.203ms
[0.272s][info][gc,start     ] GC(1) Pause Remark
[0.273s][info][gc,stringtable] GC(1) Cleaned string and symbol table, strings: 2895 processed, 0 removed, symbols: 26894 processed, 0 removed
[0.273s][info][gc            ] GC(1) Pause Remark 15M->15M(20M) 0.820ms
[0.273s][info][gc,cpu        ] GC(1) User=0.00s Sys=0.00s Real=0.00s
[0.273s][info][gc,marking    ] GC(1) Concurrent Rebuild Remembered Sets
[0.273s][info][gc,marking    ] GC(1) Concurrent Rebuild Remembered Sets 0.056ms
[0.274s][info][gc,start      ] GC(1) Pause Cleanup
[0.274s][info][gc            ] GC(1) Pause Cleanup 15M->15M(20M) 0.050ms
[0.274s][info][gc,cpu        ] GC(1) User=0.00s Sys=0.00s Real=0.00s
[0.274s][info][gc,marking    ] GC(1) Concurrent Cleanup for Next Mark
[0.274s][info][gc,marking    ] GC(1) Concurrent Cleanup for Next Mark 0.117ms
[0.274s][info][gc            ] GC(1) Concurrent Cycle 10.654ms
[0.274s][info][gc,heap,exit  ] Heap
[0.274s][info][gc,heap,exit  ]  garbage-first heap   total 20480K, used 15456K [0x00000000fec00000, 0x0000000100000000)
[0.274s][info][gc,heap,exit  ]   region size 1024K, 3 young (3072K), 2 survivors (2048K)
[0.274s][info][gc,heap,exit  ]  Metaspace       used 6520K, capacity 6603K, committed 6784K, reserved 1056768K
[0.274s][info][gc,heap,exit  ]   class space    used 571K, capacity 602K, committed 640K, reserved 1048576K