搞定Hotspot-api-白红宇

搞定Hotspot-api

阅读量：6516 次

发布时间：2019-06-24

本文共 7718 字，大约阅读时间需要 25 分钟。

目的，搞这玩意儿，无非想学习下hotspot中的java对象体系。恩直接上代码吧。

做了一个工程：

待观察类：

package hotspot.api.test;/** * hotspot 观察类 * @author  * */public class Wukong {    public static int wk_static_i = 7777777;    private int wk_instance_i;        public Wukong(int wk_instance_i) {        this.wk_instance_i = wk_instance_i;    }    public int getWk_instance_i() {        return wk_instance_i;    }}

运行线程：

package hotspot.api.test;import java.io.IOException;public class WukongRun {        public static void main(String args[]){        new Wukong(8888);        try {            System.in.read();        } catch (IOException e) {            e.printStackTrace();        }    }}

attach工具：

package hotspot.api.test;import sun.jvm.hotspot.oops.HeapVisitor;import sun.jvm.hotspot.oops.Klass;import sun.jvm.hotspot.oops.ObjectHeap;import sun.jvm.hotspot.oops.Oop;import sun.jvm.hotspot.oops.OopPrinter;import sun.jvm.hotspot.runtime.VM;public class HotspotApiTest extends sun.jvm.hotspot.tools.Tool {    public static void main(String args[]) {        HotspotApiTest ht = new HotspotApiTest();        ht.start(args);        ht.stop();    }    @Override    public void run() {        VM vm = VM.getVM();        final ObjectHeap objectHeap = vm.getObjectHeap();        objectHeap.iterate(new HeapVisitor() {            @Override            public void prologue(long l) {            }            @Override            public boolean doObj(Oop oop) {                System.out.println("");                System.out.println("OOP#" + oop);                oop.iterate(new OopPrinter(System.out), true);                System.out.println("");                System.out.println("OOP.KLASS#" + oop.getKlass());                oop.getKlass().iterate(new OopPrinter(System.out), true);                System.out.println("");                System.out.println("OOP.KLASS.MIRROR#" + oop.getKlass().getJavaMirror());                oop.getKlass().getJavaMirror().iterate(new OopPrinter(System.out), true);                System.out.println("");                System.out.println("OOP.KLASS.KLASS#" + oop.getKlass().getKlass());                oop.getKlass().getKlass().iterate(new OopPrinter(System.out), true);                System.out.println("");                System.out.println("OOP.KLASS.KLASS.KLASS#" + oop.getKlass().getKlass().getKlass());                oop.getKlass().getKlass().getKlass().iterate(new OopPrinter(System.out), true);                System.out.println("");                System.out.println("OOP.KLASS.KLASS.KLASS.KLASS#" + oop.getKlass().getKlass().getKlass().getKlass());                oop.getKlass().getKlass().getKlass().getKlass().iterate(new OopPrinter(System.out), true);                return false;            }            @Override            public void epilogue() {            }        }, new ObjectHeap.ObjectFilter() {            @Override            public boolean canInclude(Oop oop) {                Klass klass = oop.getKlass();                return klass.getName() != null && "hotspot/api/test/Wukong".equals(klass.getName().asString());            }        });    }}

首先把代码编译一下：

javac -cp /home/software/jdk1.7.0_80/lib/sa-jdi.jar -d bin -sourcepath src src/main/java/hotspot/api/test/*.java

这里边要用到sa-jdi.jar这个包；eclipse下需要专门在jre配置里导入这个包才能正常编译。

然后先到bin目录下执行：

java hotspot.api.test.WukongRun

新开窗口，执行：

java -classpath /home/software/jdk1.7.0_80/lib/sa-jdi.jar: hotspot.api.test.HotspotApiTest 3475

3475就是上边WukongRun的线程id。

输出结果：

////OOP#sun.jvm.hotspot.oops.Instance@ef44eb00Oop for hotspot/api/test/Wukong @ 0x00000000ef44eb00 (object size = 16) - _mark:     {
   0} :1 - _metadata._compressed_klass:     {
   8} :InstanceKlass for hotspot/api/test/Wukong @ 0x00000000fb062e60 - wk_instance_i:     {
   12} :8888////OOP.KLASS#sun.jvm.hotspot.oops.InstanceKlass@fb062e60InstanceKlass for hotspot/api/test/Wukong @ 0x00000000fb062e60 (object size = 568) - _mark:     {
   0} :1 - _metadata._compressed_klass:     {
   8} :InstanceKlassKlass @ 0x00000000fae00270 - _java_mirror:     {
   120} :Oop for java/lang/Class @ 0x00000000ef44eaa0 - _super:     {
   128} :InstanceKlass for java/lang/Object @ 0x00000000fae02bb0 - _layout_helper:     {
   24} :16 - _access_flags:     {
   156} :33 - _subklass:     {
   136} :null - _next_sibling:     {
   144} :InstanceKlass for java/lang/Void @ 0x00000000fb0627c0 - _alloc_count:     {
   160} :0 - _array_klasses:     {
   200} :null - _methods:     {
   208} :ObjArray @ 0x00000000fb062bd0 - _method_ordering:     {
   216} :[I @ 0x00000000fae01c30 - _local_interfaces:     {
   224} :ObjArray @ 0x00000000fae01c40 - _transitive_interfaces:     {
   232} :ObjArray @ 0x00000000fae01c40 - _fields:     {
   240} :[S @ 0x00000000fb062ba8 - _constants:     {
   248} :ConstantPool for hotspot/api/test/Wukong @ 0x00000000fb062a70 - _class_loader:     {
   256} :Oop for sun/misc/Launcher$AppClassLoader @ 0x00000000ef442c58 - _protection_domain:     {
   264} :Oop for java/security/ProtectionDomain @ 0x00000000ef44c568 - _signers:     {
   272} :null - _inner_classes:     {
   280} :[S @ 0x00000000fae01c20 - _nonstatic_field_size:     {
   360} :1 - _static_field_size:     {
   364} :1 - _static_oop_field_count:     {
   368} :0 - _nonstatic_oop_map_size:     {
   372} :0 - _is_marked_dependent:     {
   376} :0 - _init_state:     {
   498} :5 - _vtable_len:     {
   392} :6 - _itable_len:     {
   396} :2////OOP.KLASS.MIRROR#sun.jvm.hotspot.oops.Instance@ef44eaa0Oop for java/lang/Class @ 0x00000000ef44eaa0 (object size = 96) - _mark:     {
   0} :1 - _metadata._compressed_klass:     {
   8} :InstanceKlass for java/lang/Class @ 0x00000000fae160c0 - cachedConstructor:     {
   12} :null - newInstanceCallerCache:     {
   16} :null - name:     {
   20} :null - classLoader:     {
   24} :Oop for sun/misc/Launcher$AppClassLoader @ 0x00000000ef442c58 - reflectionData:     {
   28} :null - classRedefinedCount:     {
   72} :0 - genericInfo:     {
   32} :null - enumConstants:     {
   36} :null - enumConstantDirectory:     {
   40} :null - annotations:     {
   44} :null - declaredAnnotations:     {
   48} :null - lastAnnotationsRedefinedCount:     {
   76} :0 - annotationType:     {
   52} :null - classValueMap:     {
   56} :nullOop for java/lang/Class @ 0x00000000ef44eaa0 (object size = 96) - wk_static_i:     {
   88} :7777777////OOP.KLASS.KLASS#sun.jvm.hotspot.oops.InstanceKlassKlass@fae00270InstanceKlassKlass @ 0x00000000fae00270 (object size = 208) - _mark:     {
   0} :1 - _metadata._compressed_klass:     {
   8} :KlassKlass @ 0x00000000fae00000 - _java_mirror:     {
   120} :null - _super:     {
   128} :null - _layout_helper:     {
   24} :0 - _access_flags:     {
   156} :0 - _subklass:     {
   136} :null - _next_sibling:     {
   144} :null - _alloc_count:     {
   160} :0////OOP.KLASS.KLASS.KLASS#sun.jvm.hotspot.oops.KlassKlass@fae00000KlassKlass @ 0x00000000fae00000 (object size = 208) - _mark:     {
   0} :1 - _metadata._compressed_klass:     {
   8} :KlassKlass @ 0x00000000fae00000 - _java_mirror:     {
   120} :null - _super:     {
   128} :null - _layout_helper:     {
   24} :0 - _access_flags:     {
   156} :0 - _subklass:     {
   136} :null - _next_sibling:     {
   144} :null - _alloc_count:     {
   160} :0////OOP.KLASS.KLASS.KLASS.KLASS#sun.jvm.hotspot.oops.KlassKlass@fae00000KlassKlass @ 0x00000000fae00000 (object size = 208) - _mark:     {
   0} :1 - _metadata._compressed_klass:     {
   8} :KlassKlass @ 0x00000000fae00000 - _java_mirror:     {
   120} :null - _super:     {
   128} :null - _layout_helper:     {
   24} :0 - _access_flags:     {
   156} :0 - _subklass:     {
   136} :null - _next_sibling:     {
   144} :null - _alloc_count:     {
   160} :0