I tried to get system properties via "jhsdb jinfo".
However, it did not work as below:

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$ /usr/local/jdk-9/bin/jhsdb jinfo --pid 1002
Attaching to process ID 1002, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 9-ea+129
Java System Properties:

java.lang.NullPointerException
        at sun.jvm.hotspot.utilities.ObjectReader.getHashtable(jdk.hotspot.agent@9-ea/ObjectReader.java:217)
        at sun.jvm.hotspot.utilities.ObjectReader.readInstance(jdk.hotspot.agent@9-ea/ObjectReader.java:247)
        at sun.jvm.hotspot.utilities.ObjectReader.readObject(jdk.hotspot.agent@9-ea/ObjectReader.java:105)
        at sun.jvm.hotspot.runtime.VM$2.doOop(jdk.hotspot.agent@9-ea/VM.java:940)
        at sun.jvm.hotspot.oops.InstanceKlass.visitField(jdk.hotspot.agent@9-ea/InstanceKlass.java:872)
        at sun.jvm.hotspot.oops.InstanceKlass.iterateStaticFieldsInternal(jdk.hotspot.agent@9-ea/InstanceKlass.java:572)
        at sun.jvm.hotspot.oops.InstanceKlass.iterateStaticFields(jdk.hotspot.agent@9-ea/InstanceKlass.java:560)
        at sun.jvm.hotspot.runtime.VM.readSystemProperties(jdk.hotspot.agent@9-ea/VM.java:935)
        at sun.jvm.hotspot.runtime.VM.getSystemProperties(jdk.hotspot.agent@9-ea/VM.java:928)
        at sun.jvm.hotspot.tools.SysPropsDumper.run(jdk.hotspot.agent@9-ea/SysPropsDumper.java:44)
        at sun.jvm.hotspot.tools.JInfo$1.run(jdk.hotspot.agent@9-ea/JInfo.java:80)
        at sun.jvm.hotspot.tools.JInfo.run(jdk.hotspot.agent@9-ea/JInfo.java:95)
        at sun.jvm.hotspot.tools.Tool.startInternal(jdk.hotspot.agent@9-ea/Tool.java:260)
        at sun.jvm.hotspot.tools.Tool.start(jdk.hotspot.agent@9-ea/Tool.java:223)
        at sun.jvm.hotspot.tools.Tool.execute(jdk.hotspot.agent@9-ea/Tool.java:118)
        at sun.jvm.hotspot.tools.JInfo.runWithArgs(jdk.hotspot.agent@9-ea/JInfo.java:139)
        at sun.jvm.hotspot.tools.JInfo.main(jdk.hotspot.agent@9-ea/JInfo.java:144)
        at sun.jvm.hotspot.SALauncher.runJINFO(jdk.hotspot.agent@9-ea/SALauncher.java:344)
        at sun.jvm.hotspot.SALauncher.main(jdk.hotspot.agent@9-ea/SALauncher.java:425)
System Properties info not available!
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I think this is caused by JDK-8029891.
JDK-8029891 changes that j.u.Properties stores properties to j.u.c.ConcurrentHashMap.
ObjectReader should be adapted to this change.