jdk自带分析工具分析系统故障

1、jstack

Usage:
    jstack [-l] 
        (to connect to running process)
    jstack -F [-m] [-l] 
        (to connect to a hung process)
    jstack [-m] [-l]  
        (to connect to a core file)
    jstack [-m] [-l] [server_id@]
        (to connect to a remote debug server)

Options:
    -F  to force a thread dump. Use when jstack  does not respond (process is hung)
    -m  to print both java and native frames (mixed mode)
    -l  long listing. Prints additional information about locks
    -h or -help to print this help message

-F 参数强制导出线程栈，一般在线程被挂起(堵塞)时使用
-m 打印java和本地线程栈帧，native指java调用c/c++本地接口
-l 字面翻译:打印额外信息和锁，实际导出最好加上该选项
-h 列出帮助信息

案例
jstack -F -m -l 1180 > dumpStack.txt

线程栈消息文件分析工具
https://publib.boulder.ibm.com/httpserv/cookbook/Major_Tools-IBM_Thread_and_Monitor_Dump_Analyzer_TMDA.html
过往分析文章
https://blog.csdn.net/ffyyhh995511/article/details/132810006

使用场景
1:java应用占用cpu高
2:排查线程阻塞或挂起
3:查看线程运行情况，例如死锁

2、jmap

jmap
Usage:
    jmap [option] 
        (to connect to running process)
    jmap [option] 
        (to connect to a core file)
    jmap [option] [server_id@]
        (to connect to remote debug server)

where  is one of:
                   to print same info as Solaris pmap
    -heap                to print java heap summary
    -histo[:live]        to print histogram of java object heap; if the "live"
                         suboption is specified, only count live objects
    -clstats             to print class loader statistics
    -finalizerinfo       to print information on objects awaiting finalization
    -dump: to dump java heap in hprof binary format
                         dump-options:
                           live         dump only live objects; if not specified,
                                        all objects in the heap are dumped.
                           format=b     binary format
                           file=  dump heap to 
                         Example: jmap -dump:live,format=b,file=heap.bin 
    -F                   force. Use with -dump:  or -histo
                         to force a heap dump or histogram when  does not
                         respond. The "live" suboption is not supported
                         in this mode.
    -h | -help           to print this help message
    -J             to pass  directly to the runtime system

hprof 文件是 Java 的 内存快照文件(Heap Profile的缩写),格式为xxx.hprof
-histo:live只打印存活的堆对象的柱状图统计信息，现实中不实用也不常用
-finalizerinfo 打印正在等待被回收的对象信息
-F 强制dump出栈信息，不支持live选项
dump在实际中常被用到 

命令案例
jmap -dump:live,format=b,file=heap.bin 文件后缀是bin
jmap -dump:live,format=b,file=heap.hprof 文件后缀是hprof

内存堆消息文件分析工具
eclipse mat插件
过往分析文章
todo

使用场景
1:分析 OOM: OutOfMemoryError(堆)内存不足错误
2:JVM设置 -XX:+HeapDumpOnOutOfMemoryError 参数时打印的内容，该参数指应用出现oom自动dump出hprof文件

jvm堆栈资料
https://blog.csdn.net/wang0907/article/details/130544919