JMXClient.java

import java.io.*;
import java.util.*;
import java.util.stream.*;
import java.lang.reflect.*;
import javax.management.*;

import sun.tools.jconsole.*;


public class JMXClient implements AutoCloseable{

  private ProxyClient client;

  private JMXClient(ProxyClient client){
    this.client = client;
  }

  @Override
  public void close() throws Exception{
    Optional.ofNullable(client)
            .ifPresent(c -> c.disconnect());
  }

  public static void listLocalVMs(){
    LocalVirtualMachine.getAllVirtualMachines()
                       .forEach((k, v) -> System.out.println(k + ": " + v));
  }

  public static JMXClient getJMXClient(int pid)
                       throws IOException, NoSuchMethodException,
                              IllegalAccessException, InvocationTargetException{
    LocalVirtualMachine vm = LocalVirtualMachine.getLocalVirtualMachine(pid);
    if(vm == null){
      throw new RuntimeException(pid + " is not accessible!");
    }

    ProxyClient client = ProxyClient.getProxyClient(vm);

    Method connectMethod = ProxyClient.class.getDeclaredMethod(
                                                      "connect", boolean.class);
    connectMethod.setAccessible(true);
    connectMethod.invoke(client, false);

    return new JMXClient(client);
  }

  public void listMBeans() throws IOException{
    client.getMBeans(null)
          .forEach((k, v) -> System.out.print(k + ":\n" +
                                             "  " + v.getDescription() + "\n"));
  }

  private void dumpAttribute(ObjectName objectName, MBeanAttributeInfo info){
    System.out.print("  ");

    if(info.isReadable()){
      try{
        System.out.println(
                  client.getAttributes(objectName, new String[]{info.getName()})
                        .stream()
                        .map(a -> a.toString())
                        .collect(Collectors.joining(", ")));
      }
      catch(IOException e){
        throw new UncheckedIOException(e);
      }
    }
    else{
      System.out.println(info.getName());
    }

  }

  private void dumpOperation(MBeanOperationInfo info){
    System.out.print("  " + info.getReturnType() +
                     " " + info.getName() +
                     " (");
    System.out.print(Arrays.stream(info.getSignature())
                                      .map(p -> p.getType() + " " + p.getName())
                                      .collect(Collectors.joining(", ")));
    System.out.println(")");
  }

  private void dumpNotification(MBeanNotificationInfo info){
    System.out.println("  " + info.getName());
    System.out.println("    " +
                       Arrays.stream(info.getNotifTypes())
                                         .collect(Collectors.joining(", ")));
  }

  public void dumpMBean(String name) throws IOException,
                                                MalformedObjectNameException{
    ObjectName objectName = new ObjectName(name);
    MBeanInfo mbeanInfo = client.getMBeans(null)
                                .get(objectName);
    if(mbeanInfo == null){
      throw new RuntimeException(objectName + " not found");
    }

    System.out.println(objectName.toString());
    System.out.println("  " + mbeanInfo.getDescription());

    System.out.println();
    System.out.println("Attributes:");
    Arrays.stream(mbeanInfo.getAttributes())
          .forEach(a -> dumpAttribute(objectName, a));

    System.out.println();
    System.out.println("Operations:");
    Arrays.stream(mbeanInfo.getOperations())
          .forEach(o -> dumpOperation(o));

    System.out.println();
    System.out.println("Notifications:");
    Arrays.stream(mbeanInfo.getNotifications())
          .forEach(n -> dumpNotification(n));
  }

  public void invoke(String name, String operationName,
                            Object[] params, String[] signature)
               throws IOException, MalformedObjectNameException, MBeanException{
    System.out.println(client.invoke(new ObjectName(name),
                                             operationName, params, signature));
  }

  public static void main(String[] args) throws Exception{

    if(args.length == 0){
      listLocalVMs();
      return;
    }

    try(JMXClient jmxClient = JMXClient.getJMXClient(
                                             Integer.parseInt(args[1]))){

      switch(args[0]){

        case "-l":
          jmxClient.listMBeans();
          break;

        case "-d":
          jmxClient.dumpMBean(args[2]);
          break;

        case "-c": // call void operation
          jmxClient.invoke(args[2], args[3], new Object[0], new String[0]);
          break;

      }

    }

  }
}

JMXクライアント.md

何者？

コンソール環境でJMXアクセスするプログラムです。 JConsoleの内部クラス（Java 9では jdk.jconsole モジュールの中にあるもの）を使って実現しています。

将来的にはどうしたい？

JShellで動く、JMXのCLI環境にしたいなぁ、と。

使い方

$ java --add-exports jdk.jconsole/sun.tools.jconsole=ALL-UNNAMED JMXClient <オプション>

または

$ java --add-exports jdk.jconsole/sun.tools.jconsole=ALL-UNNAMED JMXClient <オプション> <PID> <引数>

オプション

• なし：アタッチ可能プロセスのリストアップ
• -l ：ターゲットのMBeanをすべて表示
• -d <PID> <オブジェクト名> ：MBeanの内容を表示
• -c <PID> <オブジェクト名> <メソッド名> ：当該メソッドの呼び出し※引数を持たないもの限定

使用例.md

コンパイル

$ javac --add-exports jdk.jconsole/sun.tools.jconsole=ALL-UNNAMED JMXClient.java

アタッチ可能プロセスの列挙

$ java --add-exports jdk.jconsole/sun.tools.jconsole=ALL-UNNAMED JMXClient
1072: LongSleep
1092: JMXClient

利用可能なMBeanをすべて表示

$ java --add-exports jdk.jconsole/sun.tools.jconsole=ALL-UNNAMED JMXClient -l 1072
java.lang:name=Metaspace,type=MemoryPool:
  Information on the management interface of the MBean
java.lang:name=CodeHeap 'profiled nmethods',type=MemoryPool:
  Information on the management interface of the MBean
JMImplementation:type=MBeanServerDelegate:
  Represents  the MBean server from the management point of view.
java.lang:type=Runtime:
  Information on the management interface of the MBean
java.lang:type=Threading:
  Information on the management interface of the MBean
java.lang:type=OperatingSystem:
  Information on the management interface of the MBean
java.nio:name=direct,type=BufferPool:
  Information on the management interface of the MBean
java.lang:type=Compilation:
  Information on the management interface of the MBean
java.lang:name=CodeHeap 'non-nmethods',type=MemoryPool:
  Information on the management interface of the MBean
java.lang:name=G1 Young Generation,type=GarbageCollector:
  Information on the management interface of the MBean
java.lang:name=CodeCacheManager,type=MemoryManager:
  Information on the management interface of the MBean
java.lang:name=Compressed Class Space,type=MemoryPool:
  Information on the management interface of the MBean
java.lang:type=Memory:
  Information on the management interface of the MBean
java.lang:name=G1 Eden Space,type=MemoryPool:
  Information on the management interface of the MBean
java.lang:name=G1 Old Gen,type=MemoryPool:
  Information on the management interface of the MBean
java.nio:name=mapped,type=BufferPool:
  Information on the management interface of the MBean
java.util.logging:type=Logging:
  Information on the management interface of the MBean
java.lang:name=G1 Old Generation,type=GarbageCollector:
  Information on the management interface of the MBean
java.lang:type=ClassLoading:
  Information on the management interface of the MBean
java.lang:name=Metaspace Manager,type=MemoryManager:
  Information on the management interface of the MBean
com.sun.management:type=DiagnosticCommand:
  Diagnostic Commands
java.lang:name=G1 Survivor Space,type=MemoryPool:
  Information on the management interface of the MBean
java.lang:name=CodeHeap 'non-profiled nmethods',type=MemoryPool:
  Information on the management interface of the MBean
com.sun.management:type=HotSpotDiagnostic:
  Information on the management interface of the MBean

MBeanの内容を表示

$ java --add-exports jdk.jconsole/sun.tools.jconsole=ALL-UNNAMED JMXClient -d 1564 "com.sun.management:type=HotSpotDiagnostic"
com.sun.management:type=HotSpotDiagnostic
  Information on the management interface of the MBean

Attributes:
  DiagnosticOptions = [Ljavax.management.openmbean.CompositeData;@385c9627
  ObjectName = com.sun.management:type=HotSpotDiagnostic

Operations:
  void dumpHeap (java.lang.String p0, boolean p1)
  javax.management.openmbean.CompositeData getVMOption (java.lang.String p0)
  void setVMOption (java.lang.String p0, java.lang.String p1)

Notifications:

メソッドの呼び出し

$ java --add-exports jdk.jconsole/sun.tools.jconsole=ALL-UNNAMED JMXClient -c 1664 "com.sun.management:type=DiagnosticCommand" gcHeapInfo
 garbage-first heap   total 30720K, used 6989K [0x00000000e2400000, 0x00000000e25000f0, 0x0000000100000000)
  region size 1024K, 6 young (6144K), 1 survivors (1024K)
 Metaspace       used 11259K, capacity 12222K, committed 12416K, reserved 1060864K
  class space    used 1326K, capacity 1544K, committed 1664K, reserved 1048576K