一、问题是怎么发现的

系统是一个定时任务系统，需要定时执行业务代码，业务代码主要是访问MYSQL数据库和缓存进行操作，该开始启动，系统日志一切正常，但是运行一段时间到凌晨后，系统就自动崩溃了，java进程没有了，只留下了程序崩溃日志如下：

cat: /proc/1/environ: Permission denied
[admin@host-11-40-38-52 ~]$ more hs_err_pid231.log
#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x00007f21a8c21325, pid=231, tid=139779725313792
#
# JRE version: Java(TM) SE Runtime Environment (8.0_20-b26) (build 1.8.0_20-b26)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.20-b23 mixed mode linux-amd64 c
ompressed oops)
# Problematic frame:
# V  [libjvm.so+0x858325]  LoadKlassNode::make(PhaseGVN&, Node*, Node*, TypePtr
const*, TypeKlassPtr const*)+0x45
#
# Core dump written. Default location: /home/admin/core or core.231
#
# If you would like to submit a bug report, please visit:
#   http://bugreport.sun.com/bugreport/crash.jsp
#

---------------  T H R E A D  ---------------

Current thread (0x00007f21a4b80800):  JavaThread "C2 CompilerThread5" daemon [_t
hread_in_native, id=398, stack(0x00007f2100cfc000,0x00007f2100dfd000)]

siginfo: si_signo: 11 (SIGSEGV), si_code: 1 (SEGV_MAPERR), si_addr: 0x0000000000
000010

Registers:
RAX=0x00007f21a48fbab0, RBX=0x00007f21a48fe4b0, RCX=0x0000000000000000, RDX=0x00
000000fffffff4
RSP=0x00007f2100df9c40, RBP=0x00007f2100df9c80, RSI=0x00007f20b00e9050, RDI=0x00
007f1fe84e3650
R8 =0x00007f21a48fe4b0, R9 =0x00007f21a48fbab0, R10=0x00007f1ffc059d90, R11=0x00
007f21a8cf3560
R12=0x00007f2100dfad00, R13=0x00007f1fe84e3650, R14=0x00007f2100dfa100, R15=0x00
007f2100df9ee0
RIP=0x00007f21a8c21325, EFLAGS=0x0000000000010296, CSGSFS=0x0000000000000033, ER
R=0x0000000000000004
  TRAPNO=0x000000000000000e

Top of Stack: (sp=0x00007f2100df9c40)
0x00007f2100df9c40:   00007f20b00e9050 00007f21a48fbab0
0x00007f2100df9c50:   00007f2100df9c80 00007f21a48fe4b0
0x00007f2100df9c60:   00007f21a48fd440 00007f1fe84e3650
0x00007f2100df9c70:   00007f21a8cf3560 00007f2100df9ee0
0x00007f2100df9c80:   00007f2100df9da0 00007f21a891acb6
0x00007f2100df9c90:   00007f1ffc5122a0 00007f20b00301d0
0x00007f2100df9ca0:   00007f2100df9ce0 00007f1ffc933fc0
0x00007f2100df9cb0:   00007f2100df9ee0 00007f1ffc933fc0
0x00007f2100df9cc0:   00007f2100df9cf0 00007f21a89ac798
0x00007f2100df9cd0:   00007f2100df9cf0 00007f2100dfad00
0x00007f2100df9ce0:   0000000000000000 0000000000000002
0x00007f2100df9cf0:   00007f1ffc933fc0 00007f1ffc93ba68
0x00007f2100df9d00:   0000000000000000 00007f1ffc93ba68
0x00007f2100df9d10:   00007f2100df9d30 00007f2100000002
0x00007f2100df9d20:   00007f1ffc93b828 0000000000000000
0x00007f2100df9d30:   00007f20b0029970 0000000500000004
0x00007f2100df9d40:   00007f20b00301d0 00007f00000001b0
0x00007f2100df9d50:   000000c700000e83 00007f1ffc93b828
0x00007f2100df9d60:   00007f2100dfa100 00007f1ffc5126a0
0x00007f2100df9d70:   0000000000001019 00007f1ffc933fc0
0x00007f2100df9d80:   00007f2100df9ee0 00007f2100df9db0
0x00007f2100df9d90:   0000000000000000 00007f2100df9fd8
0x00007f2100df9da0:   00007f2100df9df0 00007f21a8cd1b0a
0x00007f2100df9db0:   00007f2100df9ee0 0000000000000000
0x00007f2100df9dc0:   00007f1f00000001 00007f2100df9ee0
0x00007f2100df9dd0:   0000000000000000 00007f2100df9ee0
0x00007f2100df9de0:   0000000000000000 00000000000001b0
0x00007f2100df9df0:   00007f2100df9e30 00007f21a8cd46f0
0x00007f2100df9e00:   00007f2100df9e30 00007f2100dfabd0
0x00007f2100df9e10:   00007f20b00fd458 00007f2100df9ee0
0x00007f2100df9e20:   000000000000001f 00007f1ffc936508
0x00007f2100df9e30:   00007f2100df9e80 00007f21a8cd4967

Instructions: (pc=0x00007f21a8c21325)
0x00007f21a8c21305:   c0 48 8b 02 4c 8b 67 10 49 89 fe 48 89 d7 ff 50
0x00007f21a8c21315:   28 8b 50 10 31 c9 83 ea 0e 83 fa 07 48 0f 42 c8
0x00007f21a8c21325:   8b 41 10 83 e8 10 83 f8 02 0f 87 9c 01 00 00 80
0x00007f21a8c21335:   79 32 00 0f 84 92 01 00 00 49 8b 06 49 89 df 48

Register to memory mapping:

RAX=0x00007f21a48fbab0 is an unknown value
RBX=0x00007f21a48fe4b0 is an unknown value
RCX=0x0000000000000000 is an unknown value
RDX=0x00000000fffffff4 is an unknown value
RSP=0x00007f2100df9c40 is pointing into the stack for thread: 0x00007f21a4b80800
RBP=0x00007f2100df9c80 is pointing into the stack for thread: 0x00007f21a4b80800
RSI=0x00007f20b00e9050 is an unknown value
RDI=0x00007f1fe84e3650 is an unknown value
R8 =0x00007f21a48fe4b0 is an unknown value
R9 =0x00007f21a48fbab0 is an unknown value
R10=0x00007f1ffc059d90 is an unknown value
R11=0x00007f21a8cf3560: <offset 0x92a560> in /home/export/servers/jdk1.8.0_20/jr
e/lib/amd64/server/libjvm.so at 0x00007f21a83c9000
R12=0x00007f2100dfad00 is pointing into the stack for thread: 0x00007f21a4b80800
R13=0x00007f1fe84e3650 is an unknown value
R14=0x00007f2100dfa100 is pointing into the stack for thread: 0x00007f21a4b80800
R15=0x00007f2100df9ee0 is pointing into the stack for thread: 0x00007f21a4b80800


Stack: [0x00007f2100cfc000,0x00007f2100dfd000],  sp=0x00007f2100df9c40,  free sp
ace=1015k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0x858325]  LoadKlassNode::make(PhaseGVN&, Node*, Node*, TypePtr co
nst*, TypeKlassPtr const*)+0x45
V  [libjvm.so+0x551cb6]  Parse::catch_inline_exceptions(SafePointNode*)+0x946
V  [libjvm.so+0x908b0a]  Parse::do_exceptions()+0xba
V  [libjvm.so+0x90b6f0]  Parse::do_one_block()+0x180
V  [libjvm.so+0x90b967]  Parse::do_all_blocks()+0x127
V  [libjvm.so+0x90fd58]  Parse::Parse(JVMState*, ciMethod*, float, Parse*)+0x7b8
V  [libjvm.so+0x3e7d09]  ParseGenerator::generate(JVMState*, Parse*)+0x99
V  [libjvm.so+0x4931cc]  Compile::Compile(ciEnv*, C2Compiler*, ciMethod*, int, b
ool, bool, bool)+0x126c
V  [libjvm.so+0x3e67e8]  C2Compiler::compile_method(ciEnv*, ciMethod*, int)+0x19
8
V  [libjvm.so+0x49ba4a]  CompileBroker::invoke_compiler_on_method(CompileTask*)+
0xc8a
V  [libjvm.so+0x49e420]  CompileBroker::compiler_thread_loop()+0x620
V  [libjvm.so+0xa2990f]  JavaThread::thread_main_inner()+0xdf
V  [libjvm.so+0xa29a3c]  JavaThread::run()+0x11c
V  [libjvm.so+0x8e75f8]  java_start(Thread*)+0x108
C  [libpthread.so.0+0x7aa1]  start_thread+0xd1


Current CompileTask:
C2:43781461 13331   !   4       com.mysql.cj.NativeSession::execSQL (579 bytes)


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

Java Threads: ( => current thread )
  0x00007f2010003800 JavaThread "qtp1589683045-1271" [_thread_blocked, id=142149
, stack(0x00007f20fa995000,0x00007f20faa96000)]
  0x00007f1f58001800 JavaThread "Keep-Alive-Timer" daemon [_thread_blocked, id=1
40557, stack(0x00007f20f830e000,0x00007f20f840f000)]
  0x00007f1fb005e800 JavaThread "logback-1" daemon [_thread_blocked, id=42936, s
tack(0x00007f20fad99000,0x00007f20fae9a000)]
  0x00007f1f7c0c3000 JavaThread "logback-8" daemon [_thread_blocked, id=565, sta
ck(0x00007f20ea6f6000,0x00007f20ea7f7000)]
  0x00007f1f50003000 JavaThread "logback-7" daemon [_thread_blocked, id=521, sta
ck(0x00007f20fab97000,0x00007f20fac98000)]
  0x00007f1f10001000 JavaThread "logback-6" daemon [_thread_blocked, id=520, sta
ck(0x00007f20f002b000,0x00007f20f012c000)]
  0x00007f1f74004800 JavaThread "logback-5" daemon [_thread_blocked, id=519, sta
ck(0x00007f20f1830000,0x00007f20f1931000)]
  0x00007f1f5441d000 JavaThread "UMP-CheckFileRemovedThread" daemon [_thread_blo
cked, id=518, stack(0x00007f20ea7f7000,0x00007f20ea8f8000)]
  0x00007f1f5441b800 JavaThread "UMP-ProfilerFileUpdateThread" daemon [_thread_b
locked, id=517, stack(0x00007f20ea8f8000,0x00007f20ea9f9000)]
  0x00007f1f54419800 JavaThread "UMP-WriteLog2FileThread-jvmLogger" daemon [_thr
ead_blocked, id=516, stack(0x00007f20ea9f9000,0x00007f20eaafa000)]
  0x00007f1f54418000 JavaThread "UMP-WriteLog2FileThread-commonLogger" daemon [_
thread_blocked, id=515, stack(0x00007f20eaafa000,0x00007f20eabfb000)]
  0x00007f1f54416000 JavaThread "UMP-WriteLog2FileThread-tpLogger" daemon [_thre
ad_blocked, id=514, stack(0x00007f20eabfb000,0x00007f20eacfc000)]
  0x00007f1f5440f800 JavaThread "UMP-WriteLog2FileThread-bizLogger" daemon [_thr
ead_blocked, id=513, stack(0x00007f20eacfc000,0x00007f20eadfd000)]
  0x00007f1f54410800 JavaThread "UMP-WriteLog2FileThread-businessLogger" daemon
[_thread_blocked, id=512, stack(0x00007f20eadfd000,0x00007f20eaefe000)]
  0x00007f1f54408800 JavaThread "UMP-WriteLog2FileThread-aliveLogger" daemon [_t
hread_blocked, id=511, stack(0x00007f20eaefe000,0x00007f20eafff000)]
  0x00007f1f543da000 JavaThread "DatebookHikariCP2 housekeeper" daemon [_thread_
blocked, id=509, stack(0x00007f20f012c000,0x00007f20f022d000)]
  0x00007f1f543cf800 JavaThread "Jim-NioEventLoop - 1" daemon [_thread_in_native
, id=508, stack(0x00007f20f042d000,0x00007f20f052e000)]
  0x00007f1f54259800 JavaThread "SystemClock" daemon [_thread_blocked, id=507, s
tack(0x00007f20f172f000,0x00007f20f1830000)]
  0x00007f1f54216000 JavaThread "DatebookHikariCP4 housekeeper" daemon [_thread_
blocked, id=505, stack(0x00007f20f289f000,0x00007f20f29a0000)]
  0x00007f1f540b5000 JavaThread "UMP-WriteTPLogThread" daemon [_thread_blocked,
id=504, stack(0x00007f20fa490000,0x00007f20fa591000)]
  0x00007f1f50002000 JavaThread "logback-4" daemon [_thread_blocked, id=503, sta
ck(0x00007f20fa38f000,0x00007f20fa490000)]
  0x00007f1f74003000 JavaThread "logback-3" daemon [_thread_blocked, id=502, sta
ck(0x00007f20f29a0000,0x00007f20f2aa1000)]
  0x00007f21a4bc4000 JavaThread "http-nio-8001-Acceptor-0" daemon [_thread_in_na
tive, id=501, stack(0x00007f20f1d31000,0x00007f20f1e32000)]
  0x00007f21a4bc2000 JavaThread "http-nio-8001-ClientPoller-1" daemon [_thread_i
n_native, id=500, stack(0x00007f20f1e32000,0x00007f20f1f33000)]
  0x00007f21a4bc0000 JavaThread "http-nio-8001-ClientPoller-0" daemon [_thread_i
n_native, id=499, stack(0x00007f20f1f33000,0x00007f20f2034000)]
  0x00007f21a4bbe800 JavaThread "http-nio-8001-exec-10" daemon [_thread_blocked,
 id=498, stack(0x00007f20f2034000,0x00007f20f2135000)]
  0x00007f21a4958800 JavaThread "http-nio-8001-exec-9" daemon [_thread_blocked,
id=497, stack(0x00007f20f2135000,0x00007f20f2236000)]
  0x00007f21a4956800 JavaThread "http-nio-8001-exec-8" daemon [_thread_blocked,
id=496, stack(0x00007f20f2236000,0x00007f20f2337000)]
  0x00007f21a4955000 JavaThread "http-nio-8001-exec-7" daemon [_thread_blocked,
id=495, stack(0x00007f20f2337000,0x00007f20f2438000)]
  0x00007f21a4953800 JavaThread "http-nio-8001-exec-6" daemon [_thread_blocked,
id=494, stack(0x00007f20f2438000,0x00007f20f2539000)]
  0x00007f21a4952000 JavaThread "http-nio-8001-exec-5" daemon [_thread_blocked,
id=493, stack(0x00007f20f2539000,0x00007f20f263a000)]
  0x00007f21a4b7e800 JavaThread "http-nio-8001-exec-4" daemon [_thread_blocked,
id=492, stack(0x00007f20f263a000,0x00007f20f273b000)]
  0x00007f21a4b7d000 JavaThread "http-nio-8001-exec-3" daemon [_thread_blocked,
id=491, stack(0x00007f20f273b000,0x00007f20f283c000)]
  0x00007f21a4b7b800 JavaThread "http-nio-8001-exec-2" daemon [_thread_blocked,
id=490, stack(0x00007f20f2cfd000,0x00007f20f2dfe000)]
  0x00007f21a4b7a000 JavaThread "http-nio-8001-exec-1" daemon [_thread_blocked,
id=489, stack(0x00007f20f2dfe000,0x00007f20f2eff000)]
  0x00007f21a4b78800 JavaThread "ContainerBackgroundProcessor[StandardEngine[Cat
alina]]" daemon [_thread_blocked, id=488, stack(0x00007f20f2aa1000,0x00007f20f2b
a2000)]
  0x00007f1f7cb62800 JavaThread "scheduling-1" [_thread_in_native, id=487, stack
(0x00007f20f2ba2000,0x00007f20f2ca3000)]
  0x00007f1f74001000 JavaThread "logback-2" daemon [_thread_blocked, id=486, sta
ck(0x00007f20f2eff000,0x00007f20f3000000)]
  0x00007f1f7ca2b800 JavaThread "Jim-ConfigPoolingHeartbeat-1571143858733" daemo
n [_thread_in_native, id=442, stack(0x00007f20f800b000,0x00007f20f810c000)]
  0x00007f1f7c913800 JavaThread "mysql-cj-abandoned-connection-cleanup" daemon [
_thread_blocked, id=441, stack(0x00007f20f8833000,0x00007f20f8934000)]
  0x00007f1f7c7b8800 JavaThread "configurator-supervise" daemon [_thread_blocked
, id=440, stack(0x00007f20f810c000,0x00007f20f820d000)]
  0x00007f1f7c7b7000 JavaThread "Thread-51" daemon [_thread_blocked, id=439, sta
ck(0x00007f20f820d000,0x00007f20f830e000)]
  0x00007f1f7c71e000 JavaThread "JSF-Future-Checker-CB-1-T-1" daemon [_thread_bl
ocked, id=436, stack(0x00007f20f8b34000,0x00007f20f8c35000)]
  0x00007f1f7c71d800 JavaThread "JSF-Future-Checker-0-T-1" daemon [_thread_block
ed, id=435, stack(0x00007f20f9bc2000,0x00007f20f9cc3000)]
  0x00007f1f7c3ba000 JavaThread "logback-1" daemon [_thread_blocked, id=433, sta
ck(0x00007f20f9635000,0x00007f20f9736000)]
  0x00007f21a4e27800 JavaThread "NioBlockingSelector.BlockPoller-1" daemon [_thr
ead_in_native, id=429, stack(0x00007f20fa591000,0x00007f20fa692000)]
  0x00007f2030001000 JavaThread "qtp1589683045-59 Selector15" [_thread_in_native
, id=414, stack(0x00007f20fb39f000,0x00007f20fb4a0000)]
  0x00007f21a4da0800 JavaThread "GC Daemon" daemon [_thread_blocked, id=413, sta
ck(0x00007f20fbafd000,0x00007f20fbbfe000)]
  0x00007f21a4baa000 JavaThread "Service Thread" daemon [_thread_blocked, id=411
, stack(0x00007f20fbeff000,0x00007f20fc000000)]
  0x00007f21a4b9a800 JavaThread "C1 CompilerThread17" daemon [_thread_blocked, i
d=410, stack(0x00007f21000f0000,0x00007f21001f1000)]
  0x00007f21a4b98800 JavaThread "C1 CompilerThread16" daemon [_thread_blocked, i
d=409, stack(0x00007f21001f1000,0x00007f21002f2000)]
  0x00007f21a4b96800 JavaThread "C1 CompilerThread15" daemon [_thread_blocked, i
d=408, stack(0x00007f21002f2000,0x00007f21003f3000)]
  0x00007f21a4b94800 JavaThread "C1 CompilerThread14" daemon [_thread_blocked, i
d=407, stack(0x00007f21003f3000,0x00007f21004f4000)]
  0x00007f21a4b92000 JavaThread "C1 CompilerThread13" daemon [_thread_blocked, i
d=406, stack(0x00007f21004f4000,0x00007f21005f5000)]
  0x00007f21a4b90000 JavaThread "C1 CompilerThread12" daemon [_thread_blocked, i
d=405, stack(0x00007f21005f5000,0x00007f21006f6000)]
  0x00007f21a4b8e000 JavaThread "C2 CompilerThread11" daemon [_thread_blocked, i
d=404, stack(0x00007f21006f6000,0x00007f21007f7000)]
  0x00007f21a4b8b800 JavaThread "C2 CompilerThread10" daemon [_thread_blocked, i
d=403, stack(0x00007f21007f7000,0x00007f21008f8000)]
  0x00007f21a4b89800 JavaThread "C2 CompilerThread9" daemon [_thread_blocked, id
=402, stack(0x00007f21008f8000,0x00007f21009f9000)]
  0x00007f21a4b87000 JavaThread "C2 CompilerThread8" daemon [_thread_blocked, id
=401, stack(0x00007f21009f9000,0x00007f2100afa000)]
  0x00007f21a4b85000 JavaThread "C2 CompilerThread7" daemon [_thread_blocked, id
=400, stack(0x00007f2100afa000,0x00007f2100bfb000)]
  0x00007f21a4b83000 JavaThread "C2 CompilerThread6" daemon [_thread_blocked, id
=399, stack(0x00007f2100bfb000,0x00007f2100cfc000)]
=>0x00007f21a4b80800 JavaThread "C2 CompilerThread5" daemon [_thread_in_native,
id=398, stack(0x00007f2100cfc000,0x00007f2100dfd000)]
  0x00007f21a4b76800 JavaThread "C2 CompilerThread4" daemon [_thread_blocked, id
=397, stack(0x00007f2100dfd000,0x00007f2100efe000)]
  0x00007f21a4b74000 JavaThread "C2 CompilerThread3" daemon [_thread_blocked, id
=396, stack(0x00007f2100efe000,0x00007f2100fff000)]
  0x00007f21a4b72000 JavaThread "C2 CompilerThread2" daemon [_thread_blocked, id
=395, stack(0x00007f2108098000,0x00007f2108199000)]
  0x00007f21a4b6f800 JavaThread "C2 CompilerThread1" daemon [_thread_blocked, id
=394, stack(0x00007f2108199000,0x00007f210829a000)]
  0x00007f21a4b6e000 JavaThread "C2 CompilerThread0" daemon [_thread_blocked, id
=393, stack(0x00007f210829a000,0x00007f210839b000)]
  0x00007f21a4b6b000 JavaThread "qtp1589683045-38 Selector14" [_thread_in_native
, id=392, stack(0x00007f210839b000,0x00007f210849c000)]
  0x00007f21a4b69000 JavaThread "qtp1589683045-37 Selector13" [_thread_in_native
, id=391, stack(0x00007f210849c000,0x00007f210859d000)]
  0x00007f21a4b67000 JavaThread "qtp1589683045-36 Selector12" [_thread_in_native
, id=390, stack(0x00007f210859d000,0x00007f210869e000)]
  0x00007f21a4b65000 JavaThread "qtp1589683045-35 Selector11" [_thread_in_native
, id=389, stack(0x00007f210869e000,0x00007f210879f000)]
  0x00007f21a4b62800 JavaThread "qtp1589683045-34 Selector10" [_thread_in_native
, id=388, stack(0x00007f210879f000,0x00007f21088a0000)]
  0x00007f21a4b60800 JavaThread "qtp1589683045-33 Selector9" [_thread_in_native,
 id=387, stack(0x00007f21088a0000,0x00007f21089a1000)]
  0x00007f21a4b5e800 JavaThread "qtp1589683045-32 Selector8" [_thread_in_native,
 id=386, stack(0x00007f21089a1000,0x00007f2108aa2000)]
  0x00007f21a4b5c800 JavaThread "qtp1589683045-31 Selector7" [_thread_in_native,
 id=385, stack(0x00007f2108aa2000,0x00007f2108ba3000)]
  0x00007f21a4b5a800 JavaThread "qtp1589683045-30 Selector6" [_thread_in_native,
 id=384, stack(0x00007f2108ba3000,0x00007f2108ca4000)]
  0x00007f21a4b58800 JavaThread "qtp1589683045-29 Selector5" [_thread_in_native,
 id=383, stack(0x00007f2108ca4000,0x00007f2108da5000)]
  0x00007f21a4b56800 JavaThread "qtp1589683045-28 Selector4" [_thread_in_native,
 id=382, stack(0x00007f2108da5000,0x00007f2108ea6000)]
  0x00007f21a4b54800 JavaThread "qtp1589683045-27 Selector3" [_thread_in_native,
 id=381, stack(0x00007f2108ea6000,0x00007f2108fa7000)]
  0x00007f21a4b52800 JavaThread "qtp1589683045-26 Selector2" [_thread_in_native,
 id=380, stack(0x00007f2108fa7000,0x00007f21090a8000)]
  0x00007f21a4b50800 JavaThread "qtp1589683045-25 Selector1" [_thread_in_native,
 id=379, stack(0x00007f21090a8000,0x00007f21091a9000)]
  0x00007f21a49ad800 JavaThread "qtp1589683045-24 Selector0" [_thread_in_native,
 id=378, stack(0x00007f21091a9000,0x00007f21092aa000)]
  0x00007f21a49ac000 JavaThread "qtp1589683045-23 Acceptor15 SelectChannelConnec
tor@0.0.0.0:7001 STARTING" [_thread_blocked, id=377, stack(0x00007f21092aa000,0x
00007f21093ab000)]
  0x00007f21a49a8800 JavaThread "qtp1589683045-22 Acceptor14 SelectChannelConnec
tor@0.0.0.0:7001 STARTING" [_thread_blocked, id=376, stack(0x00007f21093ab000,0x
00007f21094ac000)]
  0x00007f21a49a6800 JavaThread "qtp1589683045-21 Acceptor13 SelectChannelConnec
tor@0.0.0.0:7001 STARTING" [_thread_blocked, id=375, stack(0x00007f21094ac000,0x
00007f21095ad000)]
  0x00007f21a49a4800 JavaThread "qtp1589683045-20 Acceptor12 SelectChannelConnec
tor@0.0.0.0:7001 STARTING" [_thread_blocked, id=374, stack(0x00007f21095ad000,0x
00007f21096ae000)]
  0x00007f21a49a2800 JavaThread "qtp1589683045-19 Acceptor11 SelectChannelConnec
tor@0.0.0.0:7001 STARTING" [_thread_blocked, id=373, stack(0x00007f21096ae000,0x
00007f21097af000)]
  0x00007f21a49a0800 JavaThread "qtp1589683045-18 Acceptor10 SelectChannelConnec
tor@0.0.0.0:7001 STARTING" [_thread_blocked, id=372, stack(0x00007f21097af000,0x
00007f21098b0000)]
  0x00007f21a499e800 JavaThread "qtp1589683045-17 Acceptor9 SelectChannelConnect
or@0.0.0.0:7001 STARTING" [_thread_blocked, id=371, stack(0x00007f21098b0000,0x0
0007f21099b1000)]
  0x00007f21a499d800 JavaThread "qtp1589683045-16 Acceptor7 SelectChannelConnect
or@0.0.0.0:7001 STARTING" [_thread_in_native, id=370, stack(0x00007f21099b1000,0
x00007f2109ab2000)]
  0x00007f21a4994800 JavaThread "qtp1589683045-15 Acceptor8 SelectChannelConnect
or@0.0.0.0:7001 STARTING" [_thread_blocked, id=369, stack(0x00007f2109ab2000,0x0
0007f2109bb3000)]
  0x00007f21a4992800 JavaThread "qtp1589683045-14 Acceptor6 SelectChannelConnect
or@0.0.0.0:7001 STARTING" [_thread_blocked, id=368, stack(0x00007f2109bb3000,0x0
0007f2109cb4000)]
  0x00007f21a4990800 JavaThread "qtp1589683045-13 Acceptor3 SelectChannelConnect
or@0.0.0.0:7001 STARTING" [_thread_blocked, id=367, stack(0x00007f2109cb4000,0x0
0007f2109db5000)]
  0x00007f21a498e800 JavaThread "qtp1589683045-12 Acceptor2 SelectChannelConnect
or@0.0.0.0:7001 STARTING" [_thread_blocked, id=366, stack(0x00007f2109db5000,0x0
0007f2109eb6000)]
  0x00007f21a498c800 JavaThread "qtp1589683045-11 Acceptor5 SelectChannelConnect
or@0.0.0.0:7001 STARTING" [_thread_blocked, id=365, stack(0x00007f2109eb6000,0x0
0007f2109fb7000)]
  0x00007f21a498a800 JavaThread "qtp1589683045-10 Acceptor4 SelectChannelConnect
or@0.0.0.0:7001 STARTING" [_thread_blocked, id=364, stack(0x00007f2109fb7000,0x0
0007f210a0b8000)]
  0x00007f21a4988800 JavaThread "qtp1589683045-9 Acceptor1 SelectChannelConnecto
r@0.0.0.0:7001 STARTING" [_thread_blocked, id=363, stack(0x00007f210a0b8000,0x00
007f210a1b9000)]
  0x00007f21a4987000 JavaThread "qtp1589683045-8 Acceptor0 SelectChannelConnecto
r@0.0.0.0:7001 STARTING" [_thread_blocked, id=362, stack(0x00007f210a1b9000,0x00
007f210a2ba000)]
  0x00007f21a497c000 JavaThread "HashSessionScavenger-0" daemon [_thread_blocked
, id=361, stack(0x00007f210a2ba000,0x00007f210a3bb000)]
  0x00007f21a46a5800 JavaThread "Signal Dispatcher" daemon [_thread_blocked, id=
360, stack(0x00007f210abec000,0x00007f210aced000)]
  0x00007f21a4676800 JavaThread "Finalizer" daemon [_thread_blocked, id=359, sta
ck(0x00007f210aced000,0x00007f210adee000)]
  0x00007f21a4674800 JavaThread "Reference Handler" daemon [_thread_blocked, id=
358, stack(0x00007f210adee000,0x00007f210aeef000)]
  0x00007f21a400b000 JavaThread "main" [_thread_in_native, id=243, stack(0x00007
f21a9e2b000,0x00007f21a9f2c000)]

Other Threads:
  0x00007f21a466d800 VMThread [stack: 0x00007f210aeef000,0x00007f210aff0000] [id
=355]
  0x00007f21a4bad000 WatcherThread [stack: 0x00007f20fbdfe000,0x00007f20fbeff000
] [id=412]

VM state:not at safepoint (normal execution)

VM Mutex/Monitor currently owned by a thread: None

Heap:
 PSYoungGen      total 1305088K, used 1009509K [0x000000076ab00000, 0x00000007c0
000000, 0x00000007c0000000)
  eden space 1209856K, 82% used [0x000000076ab00000,0x00000007a7b58fa8,0x0000000
7b4880000)
  from space 95232K, 10% used [0x00000007ba300000,0x00000007bac804c0,0x00000007c
0000000)
  to   space 92672K, 0% used [0x00000007b4880000,0x00000007b4880000,0x00000007ba
300000)
 ParOldGen       total 2796544K, used 50182K [0x00000006c0000000, 0x000000076ab0
0000, 0x000000076ab00000)
  object space 2796544K, 1% used [0x00000006c0000000,0x00000006c31019c8,0x000000
076ab00000)
 Metaspace       used 69176K, capacity 71536K, committed 71808K, reserved 111206
4K
  class space    used 7973K, capacity 8461K, committed 8576K, reserved 1048576K

Card table byte_map: [0x00007f21937c9000,0x00007f2193fca000] byte_map_base: 0x00
007f21901c9000

Marking Bits: (ParMarkBitMap*) 0x00007f21a9320ac0
 Begin Bits: [0x00007f20a4000000, 0x00007f20a8000000)
 End Bits:   [0x00007f20a8000000, 0x00007f20ac000000)

Polling page: 0x00007f21a9f33000

CodeCache: size=245760Kb used=45854Kb max_used=45878Kb free=199905Kb
 bounds [0x00007f219438a000, 0x00007f219709a000, 0x00007f21a338a000]
 total_blobs=11396 nmethods=10825 adapters=479
 compilation: enabled

Compilation events (10 events):
Event: 42853.758 Thread 0x00007f21a4b98800 nmethod 13322 0x00007f21967d2650 code
 [0x00007f21967d2840, 0x00007f21967d30f8]
Event: 42941.467 Thread 0x00007f21a4b89800 13327       4       java.util.concurr
ent.ScheduledThreadPoolExecutor$DelayedWorkQueue::add (9 bytes)
Event: 42941.467 Thread 0x00007f21a4b87000 13328   !   4       java.util.concurr
ent.ScheduledThreadPoolExecutor$DelayedWorkQueue::offer (124 bytes)
Event: 42941.467 Thread 0x00007f21a4b80800 13329       4       java.util.concurr
ent.ThreadPoolExecutor::ensurePrestart (41 bytes)
Event: 42941.469 Thread 0x00007f21a4b80800 nmethod 13329 0x00007f21967d0dd0 code
 [0x00007f21967d0f20, 0x00007f21967d0ff8]
Event: 42941.493 Thread 0x00007f21a4b87000 nmethod 13328 0x00007f219708a2d0 code
 [0x00007f219708a540, 0x00007f219708b680]
Event: 42941.493 Thread 0x00007f21a4b89800 nmethod 13327 0x00007f2197070390 code
 [0x00007f2197070600, 0x00007f2197071700]
Event: 43421.467 Thread 0x00007f21a4b74000 13330       4       com.mysql.cj.resu
lt.DefaultColumnDefinition::<init> (41 bytes)
Event: 43421.469 Thread 0x00007f21a4b74000 nmethod 13330 0x00007f2196854910 code
 [0x00007f2196854a60, 0x00007f2196854b78]
Event: 43781.449 Thread 0x00007f21a4b80800 13331   !   4       com.mysql.cj.Nati
veSession::execSQL (579 bytes)

GC Heap History (10 events):
Event: 2901.101 GC heap before
{Heap before GC invocations=9 (full 3):
 PSYoungGen      total 1223168K, used 1048576K [0x000000076ab00000, 0x00000007c0
000000, 0x00000007c0000000)
  eden space 1048576K, 100% used [0x000000076ab00000,0x00000007aab00000,0x000000
07aab00000)
  from space 174592K, 0% used [0x00000007aab00000,0x00000007aab00000,0x00000007b
5580000)
  to   space 101376K, 0% used [0x00000007b9d00000,0x00000007b9d00000,0x00000007c
0000000)
 ParOldGen       total 2796544K, used 50126K [0x00000006c0000000, 0x000000076ab0
0000, 0x000000076ab00000)
  object space 2796544K, 1% used [0x00000006c0000000,0x00000006c30f39b8,0x000000
076ab00000)
 Metaspace       used 67592K, capacity 69946K, committed 70144K, reserved 111206
4K
  class space    used 7943K, capacity 8414K, committed 8448K, reserved 1048576K
Event: 2901.121 GC heap after
Heap after GC invocations=9 (full 3):
 PSYoungGen      total 1296896K, used 14251K [0x000000076ab00000, 0x00000007c000
0000, 0x00000007c0000000)
  eden space 1195520K, 0% used [0x000000076ab00000,0x000000076ab00000,0x00000007
b3a80000)
  from space 101376K, 14% used [0x00000007b9d00000,0x00000007baaeaf98,0x00000007
c0000000)
  to   space 100864K, 0% used [0x00000007b3a80000,0x00000007b3a80000,0x00000007b
9d00000)
 ParOldGen       total 2796544K, used 50150K [0x00000006c0000000, 0x000000076ab0
0000, 0x000000076ab00000)
  object space 2796544K, 1% used [0x00000006c0000000,0x00000006c30f99c8,0x000000
076ab00000)
 Metaspace       used 67592K, capacity 69946K, committed 70144K, reserved 111206
4K
  class space    used 7943K, capacity 8414K, committed 8448K, reserved 1048576K
}
Event: 10747.104 GC heap before
{Heap before GC invocations=10 (full 3):
 PSYoungGen      total 1296896K, used 1209771K [0x000000076ab00000, 0x00000007c0
000000, 0x00000007c0000000)
  eden space 1195520K, 100% used [0x000000076ab00000,0x00000007b3a80000,0x000000
07b3a80000)
  from space 101376K, 14% used [0x00000007b9d00000,0x00000007baaeaf98,0x00000007
c0000000)
  to   space 100864K, 0% used [0x00000007b3a80000,0x00000007b3a80000,0x00000007b
9d00000)
 ParOldGen       total 2796544K, used 50150K [0x00000006c0000000, 0x000000076ab0
0000, 0x000000076ab00000)
  object space 2796544K, 1% used [0x00000006c0000000,0x00000006c30f99c8,0x000000
076ab00000)
 Metaspace       used 68322K, capacity 70672K, committed 70912K, reserved 111206
4K
  class space    used 7963K, capacity 8423K, committed 8448K, reserved 1048576K
Event: 10747.119 GC heap after
Heap after GC invocations=10 (full 3):
 PSYoungGen      total 1296384K, used 10324K [0x000000076ab00000, 0x00000007c000
0000, 0x00000007c0000000)
  eden space 1195520K, 0% used [0x000000076ab00000,0x000000076ab00000,0x00000007
b3a80000)
  from space 100864K, 10% used [0x00000007b3a80000,0x00000007b44951c8,0x00000007
b9d00000)
  to   space 99840K, 0% used [0x00000007b9e80000,0x00000007b9e80000,0x00000007c0
000000)
 ParOldGen       total 2796544K, used 50158K [0x00000006c0000000, 0x000000076ab0
0000, 0x000000076ab00000)
  object space 2796544K, 1% used [0x00000006c0000000,0x00000006c30fb9c8,0x000000
076ab00000)
 Metaspace       used 68322K, capacity 70672K, committed 70912K, reserved 111206
4K
  class space    used 7963K, capacity 8423K, committed 8448K, reserved 1048576K
}
Event: 18892.422 GC heap before
{Heap before GC invocations=11 (full 3):
 PSYoungGen      total 1296384K, used 1205844K [0x000000076ab00000, 0x00000007c0
000000, 0x00000007c0000000)
  eden space 1195520K, 100% used [0x000000076ab00000,0x00000007b3a80000,0x000000
07b3a80000)
  from space 100864K, 10% used [0x00000007b3a80000,0x00000007b44951c8,0x00000007
b9d00000)
  to   space 99840K, 0% used [0x00000007b9e80000,0x00000007b9e80000,0x00000007c0
000000)
 ParOldGen       total 2796544K, used 50158K [0x00000006c0000000, 0x000000076ab0
0000, 0x000000076ab00000)
  object space 2796544K, 1% used [0x00000006c0000000,0x00000006c30fb9c8,0x000000
076ab00000)
 Metaspace       used 68759K, capacity 71020K, committed 71168K, reserved 111206
4K
  class space    used 7970K, capacity 8429K, committed 8448K, reserved 1048576K
Event: 18892.439 GC heap after
Heap after GC invocations=11 (full 3):
 PSYoungGen      total 1299968K, used 9668K [0x000000076ab00000, 0x00000007c0000
000, 0x00000007c0000000)
  eden space 1200128K, 0% used [0x000000076ab00000,0x000000076ab00000,0x00000007
b3f00000)
  from space 99840K, 9% used [0x00000007b9e80000,0x00000007ba7f11f8,0x00000007c0
000000)
  to   space 97792K, 0% used [0x00000007b3f00000,0x00000007b3f00000,0x00000007b9
e80000)
 ParOldGen       total 2796544K, used 50166K [0x00000006c0000000, 0x000000076ab0
0000, 0x000000076ab00000)
  object space 2796544K, 1% used [0x00000006c0000000,0x00000006c30fd9c8,0x000000
076ab00000)
 Metaspace       used 68759K, capacity 71020K, committed 71168K, reserved 111206
4K
  class space    used 7970K, capacity 8429K, committed 8448K, reserved 1048576K
}
Event: 27681.725 GC heap before
{Heap before GC invocations=12 (full 3):
 PSYoungGen      total 1299968K, used 1209796K [0x000000076ab00000, 0x00000007c0
000000, 0x00000007c0000000)
  eden space 1200128K, 100% used [0x000000076ab00000,0x00000007b3f00000,0x000000
07b3f00000)
  from space 99840K, 9% used [0x00000007b9e80000,0x00000007ba7f11f8,0x00000007c0
000000)
  to   space 97792K, 0% used [0x00000007b3f00000,0x00000007b3f00000,0x00000007b9
e80000)
 ParOldGen       total 2796544K, used 50166K [0x00000006c0000000, 0x000000076ab0
0000, 0x000000076ab00000)
  object space 2796544K, 1% used [0x00000006c0000000,0x00000006c30fd9c8,0x000000
076ab00000)
 Metaspace       used 68898K, capacity 71216K, committed 71424K, reserved 111206
4K
  class space    used 7971K, capacity 8429K, committed 8448K, reserved 1048576K
Event: 27681.740 GC heap after
Heap after GC invocations=12 (full 3):
 PSYoungGen      total 1297920K, used 9809K [0x000000076ab00000, 0x00000007c0000
000, 0x00000007c0000000)
  eden space 1200128K, 0% used [0x000000076ab00000,0x000000076ab00000,0x00000007
b3f00000)
  from space 97792K, 10% used [0x00000007b3f00000,0x00000007b48944d0,0x00000007b
9e80000)
  to   space 95232K, 0% used [0x00000007ba300000,0x00000007ba300000,0x00000007c0
000000)
 ParOldGen       total 2796544K, used 50174K [0x00000006c0000000, 0x000000076ab0
0000, 0x000000076ab00000)
  object space 2796544K, 1% used [0x00000006c0000000,0x00000006c30ff9c8,0x000000
076ab00000)
 Metaspace       used 68898K, capacity 71216K, committed 71424K, reserved 111206
4K
  class space    used 7971K, capacity 8429K, committed 8448K, reserved 1048576K
}
Event: 36688.570 GC heap before
{Heap before GC invocations=13 (full 3):
 PSYoungGen      total 1297920K, used 1209937K [0x000000076ab00000, 0x00000007c0
000000, 0x00000007c0000000)
  eden space 1200128K, 100% used [0x000000076ab00000,0x00000007b3f00000,0x000000
07b3f00000)
  from space 97792K, 10% used [0x00000007b3f00000,0x00000007b48944d0,0x00000007b
9e80000)
  to   space 95232K, 0% used [0x00000007ba300000,0x00000007ba300000,0x00000007c0
000000)
 ParOldGen       total 2796544K, used 50174K [0x00000006c0000000, 0x000000076ab0
0000, 0x000000076ab00000)
  object space 2796544K, 1% used [0x00000006c0000000,0x00000006c30ff9c8,0x000000
076ab00000)
 Metaspace       used 69049K, capacity 71376K, committed 71552K, reserved 111206
4K
  class space    used 7972K, capacity 8461K, committed 8576K, reserved 1048576K
Event: 36688.584 GC heap after
Heap after GC invocations=13 (full 3):
 PSYoungGen      total 1305088K, used 9729K [0x000000076ab00000, 0x00000007c0000
000, 0x00000007c0000000)
  eden space 1209856K, 0% used [0x000000076ab00000,0x000000076ab00000,0x00000007
b4880000)
  from space 95232K, 10% used [0x00000007ba300000,0x00000007bac804c0,0x00000007c
0000000)
  to   space 92672K, 0% used [0x00000007b4880000,0x00000007b4880000,0x00000007ba
300000)
 ParOldGen       total 2796544K, used 50182K [0x00000006c0000000, 0x000000076ab0
0000, 0x000000076ab00000)
  object space 2796544K, 1% used [0x00000006c0000000,0x00000006c31019c8,0x000000
076ab00000)
 Metaspace       used 69049K, capacity 71376K, committed 71552K, reserved 111206
4K
  class space    used 7972K, capacity 8461K, committed 8576K, reserved 1048576K
}

Deoptimization events (10 events):
Event: 12281.446 Thread 0x00007f1f7cb62800 Uncommon trap: reason=unreached actio
n=reinterpret pc=0x00007f2195f964f0 method=com.mysql.cj.result.DefaultColumnDefi
nition.findColumn(Ljava/lang/String;ZI)I @ 28
Event: 13726.994 Thread 0x00007f1f74001000 Uncommon trap: reason=unreached actio
n=reinterpret pc=0x00007f2196c65958 method=java.util.concurrent.ScheduledThreadP
oolExecutor$DelayedWorkQueue.take()Ljava/util/concurrent/RunnableScheduledFuture
; @ 59
Event: 14951.443 Thread 0x00007f1f7cb62800 Uncommon trap: reason=range_check act
ion=make_not_entrant pc=0x00007f21966609f0 method=java.util.DualPivotQuicksort.s
ort([IIIZ)V @ 56
Event: 14951.507 Thread 0x00007f1f543cf800 Uncommon trap: reason=unreached actio
n=reinterpret pc=0x00007f2196a0fad0 method=io.netty.util.internal.shaded.org.jct
ools.queues.MpscArrayQueue.poll()Ljava/lang/Object; @ 28
Event: 14951.507 Thread 0x00007f1f543cf800 Uncommon trap: reason=unreached actio
n=reinterpret pc=0x00007f2196196cf8 method=io.netty.buffer.PooledByteBuf.interna
lNioBuffer()Ljava/nio/ByteBuffer; @ 6
Event: 16841.448 Thread 0x00007f1f543cf800 Uncommon trap: reason=unreached actio
n=reinterpret pc=0x00007f21965db2ec method=java.util.concurrent.locks.AbstractQu
euedSynchronizer.doReleaseShared()V @ 69
Event: 43243.574 Thread 0x00007f1f54408800 Uncommon trap: reason=unreached actio
n=reinterpret pc=0x00007f21959945c4 method=com.jd.ump.profiler.util.MessagesStor
e$WriteLog2File.run()V @ 22
Event: 43243.574 Thread 0x00007f1f54410800 Uncommon trap: reason=unreached actio
n=reinterpret pc=0x00007f21959945c4 method=com.jd.ump.profiler.util.MessagesStor
e$WriteLog2File.run()V @ 22
Event: 43243.575 Thread 0x00007f1f5440f800 Uncommon trap: reason=unreached actio
n=reinterpret pc=0x00007f21959945c4 method=com.jd.ump.profiler.util.MessagesStor
e$WriteLog2File.run()V @ 22
Event: 43243.575 Thread 0x00007f1f54418000 Uncommon trap: reason=unreached actio
n=reinterpret pc=0x00007f21959945c4 method=com.jd.ump.profiler.util.MessagesStor
e$WriteLog2File.run()V @ 22

Internal exceptions (10 events):
Event: 42812.465 Thread 0x00007f1f04001000 Exception <a 'java/net/SocketExceptio
n'> (0x000000079fe54f30) thrown at [/HUDSON/workspace/8-2-build-linux-amd64/jdk8
u20/1074/hotspot/src/share/vm/prims/jni.cpp, line 716]
Event: 42812.466 Thread 0x00007f1f04001000 Exception <a 'java/net/SocketExceptio
n': Socket closed> (0x000000079fe57398) thrown at [/HUDSON/workspace/8-2-build-l
inux-amd64/jdk8u20/1074/hotspot/src/share/vm/prims/jni.cpp, line 742]
Event: 42813.148 Thread 0x00007f1f04001000 Exception <a 'java/net/SocketExceptio
n'> (0x000000079fe578c0) thrown at [/HUDSON/workspace/8-2-build-linux-amd64/jdk8
u20/1074/hotspot/src/share/vm/prims/jni.cpp, line 716]
Event: 42813.148 Thread 0x00007f1f04001000 Exception <a 'java/net/SocketExceptio
n': Socket closed> (0x000000079fe59d28) thrown at [/HUDSON/workspace/8-2-build-l
inux-amd64/jdk8u20/1074/hotspot/src/share/vm/prims/jni.cpp, line 742]
Event: 42821.451 Thread 0x00007f1f7cb62800 Exception <a 'java/net/SocketExceptio
n'> (0x000000079f1a5d90) thrown at [/HUDSON/workspace/8-2-build-linux-amd64/jdk8
u20/1074/hotspot/src/share/vm/prims/jni.cpp, line 716]

二、排查问题的详细过程

当JVM 的初始化完成后，类在调用执行过程中，执行引擎会把字节码转为机器码，然后在操作系统中才能执行。在字节码转换为机器码的过程中，虚拟机中还存在着一道编译，那就是即时编译。

最初，JVM 中的字节码是由解释器（ Interpreter ）完成编译的，当虚拟机发现某个方法或代码块的运行特别频繁的时候，就会把这些代码认定为热点代码。

为了提高热点代码的执行效率，在运行时，即时编译器（JIT，Just In Time）会把这些代码编译成与本地平台相关的机器码，并进行各层次的优化，然后保存到内存中。

C1 编译器

C1 编译器是一个简单快速的编译器，主要的关注点在于局部性的优化，适用于执行时间较短或对启动性能有要求的程序，也称为Client Compiler，例如，GUI 应用对界面启动速度就有一定要求。

C2 编译器

C2 编译器是为长期运行的服务器端应用程序做性能调优的编译器，适用于执行时间较长或对峰值性能有要求的程序，也称为Server Compiler，例如，服务器上长期运行的 Java 应用对稳定运行就有一定的要求。

触发标准

在 HotSpot 虚拟机中，热点探测是 JIT 的触发标准。

热点探测是基于计数器的热点探测，采用这种方法的虚拟机会为每个方法建立计数器统计方法的执行次数，如果执行次数超过一定的阈值就认为它是“热点方法” 。虚拟机为每个方法准备了两类计数器：方法调用计数器（Invocation Counter）和回边计数器（Back Edge Counter）。在确定虚拟机运行参数的前提下，这两个计数器都有一个确定的阈值，当计数器超过阈值溢出了，就会触发 JIT 编译。

方法调用计数器

方法调用计数器用于统计方法被调用的次数，默认阈值在 C1 模式下是 1500 次，在 C2 模式在是 10000 次，可通过-XX: CompileThreshold来设定；而在分层编译的情况下-XX: CompileThreshold指定的阈值将失效，此时将会根据当前待编译的方法数以及编译线程数来动态调整。当方法计数器和回边计数器之和超过方法计数器阈值时，就会触发 JIT 编译器。

显然是定时任务一直在执行某一段程序代码，触发了JIT编译，所以JVM对该段代码进行JIT编译，但是在编译过程中出现了异常，导致JVM异常退出。

三、如何解决问题

既然知道了是由于热点代码执行次数过多触发了JIT编译，所以有两种解决方案

1：通过JVM命令进制对某个方法进行JIT编译，JVM相关配置命令如下

java -Xint -version ## 解释模式，输出interpreted mode

java –Xcomp -version ##编译模式，输出compiled mode

java -Xmixed -version ##混合模式，输出mixed mode

-XX:+PrintCompilation (输出jit编译信息)

-XX:CompileCommand=exclude,the/package/and/Class,methodName #判处指定的方法不做jit优化

-XX:CompileCommand='compileonly,java/lang/StringBuffer.*' #指定方法做编译

-XX:CompileThreshold=1000 #通过JIT编译器，将方法编译成机器码的触发阀值，可以理解为调用方法的次数，例如调1000次，将方法编译为机器码

2：考虑到之前使用老版本的mysql连接驱动，程序一直没有问题，所以对mysql驱动包进行降级，恢复到稳定版本,有问题的版本为spring-boot-2.1.6.RELEASE 依赖的mysql驱动

作者：京东零售 曹志飞

来源：京东云开发者社区 转载请注明来源