jps, jstat指令

JPS指令常用來檢視linux伺服器上的JVM的執行個體

-l：輸出這個application的main class的full package name，或者main class的jar file路徑

jps -l 
              3002 /opt/j2sdk1.5.0/demo/jfc/Java2D/Java2Demo.JAR
              2857 sun.tools.jstatd.jstatd
           

-v： 輸出JVM的arguments

22228 Jps -Denv.class.path=.:/Library/Java/JavaVirtualMachines/jdk1.8.0_101.jdk/Contents/Home/lib/ -Dapplication.home=/Library/Java/JavaVirtualMachines/jdk1.8.0_101.jdk/Contents/Home -Xms8m
22133 AppMain -Dmaven.home=/Applications/IntelliJ IDEA.app/Contents/plugins/maven/lib/maven3 -Dclassworlds.conf=/Applications/IntelliJ IDEA.app/Contents/plugins/maven/lib/maven3/bin/m2.conf -Didea.launcher.port=7532 -Didea.launcher.bin.path=/Applications/IntelliJ IDEA.app/Contents/bin -Dfile.encoding=UTF-8
15389  -Dfile.encoding=UTF-8 -XX:+UseConcMarkSweepGC -XX:SoftRefLRUPolicyMSPerMB=50 -ea -Dsun.io.useCanonCaches=false -Djava.net.preferIPv4Stack=true -XX:+HeapDumpOnOutOfMemoryError -XX:-OmitStackTraceInFastThrow -Xverify:none -XX:ErrorFile=/Users/java_error_in_idea_%p.log -XX:HeapDumpPath=/Users/java_error_in_idea.hprof -Xbootclasspath/a:../lib/boot.jar -Xms128m -Xmx2048m -XX:ReservedCodeCacheSize=240m -XX:+UseCompressedOops -XX:MaxPermSize=1024m -Djb.vmOptionsFile=/Users/Library/Preferences/IntelliJIdea2016.2/idea.vmoptions -Didea.java.redist=jdk-bundled -Didea.home.path=/Applications/IntelliJ IDEA.app/Contents -Didea.executable=idea -Didea.paths.selector=IntelliJIdea2016.2
           

當然也可以疊加使用

jps -lv

22133 com.intellij.rt.execution.application.AppMain -Dmaven.home=/Applications/IntelliJ IDEA.app/Contents/plugins/maven/lib/maven3 -Dclassworlds.conf=/Applications/IntelliJ IDEA.app/Contents/plugins/maven/lib/maven3/bin/m2.conf -Didea.launcher.port=7532 -Didea.launcher.bin.path=/Applications/IntelliJ IDEA.app/Contents/bin -Dfile.encoding=UTF-8
22235 sun.tools.jps.Jps -Denv.class.path=.:/Library/Java/JavaVirtualMachines/jdk1.8.0_101.jdk/Contents/Home/lib/ -Dapplication.home=/Library/Java/JavaVirtualMachines/jdk1.8.0_101.jdk/Contents/Home -Xms8m
           

jstat指令常用來監控某個jvm程序的記憶體占用問題

jstat -gc #pid

S0C    S1C    S0U    S1U      EC       EU        OC         OU       MC     MU    CCSC   CCSU   YGC     YGCT    FGC    FGCT     GCT
26752.0 26752.0 6877.0  0.0   214592.0 203198.4  535784.0   361816.3  259284.0 242894.3 36336.0 32603.2    600    9.602  56     51.876   61.478
           

jstat -gc #pid #interval 最後一個參數定義列印的間隔時間

S0C    S1C    S0U    S1U      EC       EU        OC         OU       MC     MU    CCSC   CCSU   YGC     YGCT    FGC    FGCT     GCT
26752.0 26752.0  0.0   9500.9 214592.0 66557.6   535784.0   361816.3  259284.0 242895.6 36336.0 32603.2    601    9.612  56     51.876   61.488
26752.0 26752.0  0.0   9500.9 214592.0 66716.9   535784.0   361816.3  259284.0 242895.6 36336.0 32603.2    601    9.612  56     51.876   61.488
26752.0 26752.0  0.0   9500.9 214592.0 66741.6   535784.0   361816.3  259284.0 242895.6 36336.0 32603.2    601    9.612  56     51.876   61.488
26752.0 26752.0  0.0   9500.9 214592.0 66751.4   535784.0   361816.3  259284.0 242895.6 36336.0 32603.2    601    9.612  56     51.876   61.488
26752.0 26752.0  0.0   9500.9 214592.0 66751.4   535784.0   361816.3  259284.0 242895.6 36336.0 32603.2    601    9.612  56     51.876   61.488
26752.0 26752.0  0.0   9500.9 214592.0 66751.4   535784.0   361816.3  259284.0 242895.6 36336.0 32603.2    601    9.612  56     51.876   61.488
           

jstat -class #pid 列印該程序加載了多少個類，以及這些類所占用的空間；未加載多少個class，以及占用的空間

Loaded  Bytes  Unloaded  Bytes     Time
 49281 92067.2     3313  4221.3      33.73