Table of Contents

JNet: PowerShell Module

Installation

To install the tool executes the following command within a PowerShell shell:

Install-Module -Name MASES.JNetPS

If the above command fails, reporting errors related to authenticode, use the following command:

Install-Module -Name MASES.JNetPS -SkipPublisherCheck

Usage

To use the PowerShell interface (JNetPS) runs the following commands within a PowerShell shell:

Initialization

  • The following cmdlet initialize the environment:
Start-JNetPS [arguments]

Execution

Now everything is ready and you can create objects like in the following snippet:

$var = New-JObject -Class java.lang.String -Arguments "Hello from"
$var.ToString()
$var = $var.concat(" JNetPS")
$var.ToString()

the output will be:

Hello from
Hello from JNetPS

JMX example

From version 1.5.0 new JMX comlets are available; the tutorial in https://docs.oracle.com/javase/tutorial/jmx/remote/custom.html can be reproduced in PowerShell:

$url = New-JMXServiceURL "service:jmx:rmi:///jndi/rmi://:9999/jmxrmi"
$connector = Get-JMXConnector $url

$domains = Get-Domains $connector
$defaultdomain = Get-DefaultDomain $connector
$names = Get-QueryNames $connector

$mbeanName = New-ObjectName "com.example:type=Hello"
$mbeanProxy = New-MBeanProxy -Connector $connector -ObjectName $mbeanName -InterfaceName "HelloMBean" -WithNotificationEmitter

[Action[JavaX.Management.Notification, System.Object]]$action = {param($notification, $handback) Write-Host "Notification message is $notification.Message"}
$listener = New-NotificationListener $action

Add-NotificationListener $connector $mbeanName $listener 

mbeanProxy.getCacheSize() // this use dynamic on mbeanProxy

Cmdlet available

jnetps accepts the following cmdlets:

  • Start-JNetPS: Initialize the engine and shall be the first command to be invoked. The arguments are:
    • LicensePath
    • JDKHome
    • JVMPath
    • JNIVerbosity
    • JNIOutputFile
    • JmxPort
    • EnableDebug
    • JavaDebugPort
    • DebugSuspendFlag
    • JavaDebugOpts
    • HeapSize
    • InitialHeapSize
    • LogClassPath
  • Invoke-JCommand: executes the main method of a specific Java Main-Class in argument and exit. The arguments are:
    • MainClass
    • Arguments
  • New-JObject: Creates a new JVM object of the class specified in argument using the parameters within command line for constructor. The arguments are:
    • Class
    • Arguments
  • Get-ClassForName: returns a Class from the class name
    • ClassName

From version 1.5.0 new JMX comlets are available:

  • Add-NotificationListener: adds a notification listener and filter on a JMXConnector
  • Get-DefaultDomain: get default domain from a JMXConnector
  • Get-Domains: get all domains from a JMXConnector
  • Get-IsMXBeanInterface: verify if the class name is an MBean interface
  • Get-JMXConnector: get a JMXConnector
  • Get-MBeanCount: get the number of MBean from a JMXConnector
  • Get-MBeanInfo: get the MBeanInfo from an ObjectName using a JMXConnector
  • Get-QueryNames: get the ObjectNames using a JMXConnector
  • Invoke-QueryAnd: execute Query.And
  • Invoke-QueryAnySubString: execute Query.AnySubString
  • Invoke-QueryAttr: execute Query.Attr
  • Invoke-QueryBetween: execute Query.Between
  • Invoke-QueryClassattr: execute Query.Classattr
  • Invoke-QueryDiv: execute Query.Div
  • Invoke-QueryEq: execute Query.Eq
  • Invoke-QueryFinalSubString: execute Query.FinalSubString
  • Invoke-QueryGeq: execute Query.Geq
  • Invoke-QueryGt: execute Query.Gt
  • Invoke-QueryIn: execute Query.In
  • Invoke-QueryInitialSubString: execute Query.nitialSubString
  • Invoke-QueryIsInstanceOf: execute Query.IsInstanceOf
  • Invoke-QueryLeq: execute Query.Leq
  • Invoke-QueryLt: execute Query.Lt
  • Invoke-QueryMatch: execute Query.Match
  • Invoke-QueryMinus: execute Query.Minus
  • Invoke-QueryNot: execute Query.Not
  • Invoke-QueryOr: execute Query.Or
  • Invoke-QueryPlus: execute Query.Plus
  • Invoke-QueryTimes: execute Query.Times
  • Invoke-QueryValue: execute Query.Value
  • New-AttributeChangeNotificationFilter: create a new AttributeChangeNotificationFilter to be used in Add-NotificationListener
  • New-JMXServiceURL: create a new JMXServiceURL to be used in Get-JMXConnector
  • New-MBeanProxy: get a MBeanProxy from a JMXConnector
  • New-MXBeanProxy: get a MXBeanProxy from a JMXConnector
  • New-NotificationFilterSupport: create a new NotificationFilterSupport to be used in Add-NotificationListener
  • New-NotificationListener: create a new NotificationListener to be used in Add-NotificationListener
  • New-ObjectName: create a new ObjectName to be used in Get-JMXConnector
  • Remove-NotificationListener: removes a notification listener and filter from a JMXConnector

JVM identification

One of the most important command-line switch is JVMPath: it can be used to set-up the location of the JVM library (jvm.dll/libjvm.so) if JCOBridge is not able to identify a suitable JRE installation.

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