Get task manager list via SWT? - java

Is there a way using SWT to get a list of all processes currently running (similar to executing tasklist.exe/tlist.exe on Windows)? If so, is there sample code available?
Ideally this would be done programmatically only (no third party tools).
My app monitors the process list and needs to support Windows 2000/Server 2003/XP Home/XP Pro/Vista
Thanks in advance.

This does not seem to be possible using SWT or even Java for that matter is a poor fit across multiple platforms. I ended up using JNI to list the running tasks. This works across all OS that I required. I found a good working example at the address below that I integrated into my app. Has multiple features implemented such as listing processes, killing processes, finding if specific EXE is running, and more. Hope this helps someone in the future.
http://www.codeproject.com/KB/java/jnisample.aspx

Related

Is it possible to build a web automation that can run through a browser?

I have created a Java program that utilizes Chrome Driver, Selenium, and Java Excel API. The program is used to automate a few different processes on Google Chrome. Currently, setting up this automation is more complicated than I would like it to be: the user needs to download a zipped folder, unzip it, download the Java Runtime Environment, and launch the program using the executable.
My goal is to simplify the installation of the automation. Ideally, a user would come to a SharePoint website, fill out a form with the parameters of the automation (potentially upload an Excel Workbook), click an "execute" button, and the automation would run. As a result, the automation would run seamlessly across platforms (Windows and MacOS) without any modifications.
I have researched changing the programming language to achieve this functionality. I concluded that a different language could remove the need for a Java Runtime Environment download, but it would still require some type of installation process. Additionally, I have researched using HTML/JavaScript, but I concluded that this is not possible because the functionality (triggering a web automation from a website) could be used maliciously without the user's knowledge. Finally, I began researching containerization through Docker. This solution seems promising but I do not know enough about it to determine if it is the appropriate solution.
What would be the best route to achieve the results that I am looking for (outlined in the second paragraph)? I have access to enterprise-grade databases that I thought may be useful. Would it be possible to have the form trigger a virtual machine to run the automation on a remote database and then output the result to the user once it has finished?
Thank you in advance for any guidance you can provide. I do not know much about making a Java program into an enterprise-grade application so any information about what to research is extremely useful. Finally, please do not hesitate to correct my logic at any point in this question as I may have drawn the wrong conclusions from my research.
You want to look into creating a jar file with your selenium code.

Automated updates for Java applications [duplicate]

I would like to implement a java application (server application) that can download a new version (.jar file) from a given url, and then update itself at runtime.
What is the best way to do this and is it possible?
I guess that the application can download a new .jar file and start it. But how should I do the handover, e.g. know when the new application is started and then exit. Or is there a better way to do this?
The basic structure of a solution is as follows:
There is a main loop responsible for repeatedly loading the latest version of the app (if required) and launching it.
The application does its thing, but periodically checks the download URL. If it detects a new version it exits back to the launcher.
There are a number of ways you could implement this. For example:
The launcher could be a wrapper script or binary application that starts a new JVM to run the application from a JAR file that gets replaced.
The launcher could be a Java application that creates a classloader for the new JAR, loads an entrypoint class and calls some method on it. If you do it this way, you have to watch for classloader storage leaks, but that's not difficult. (You just need to make sure that no objects with classes loaded from the JAR are reachable after you relaunch.)
The advantages of the external wrapper approach are:
you only need one JAR,
you can replace the entire Java app,
any secondary threads created by the app, etc will go away without special shutdown logic, and
you can also deal with recovery from application crashes, etc.
The second approach requires two JARs, but has the following advantages:
the solution is pure Java and portable,
the changeover will be quicker, and
you can more easily retain state across the restart (modulo leakage issues).
The "best" way depends on your specific requirements.
It should also be noted that:
There are security risks with auto-updating. In general, if the server that provides the updates is compromised, or if the mechanisms for providing the updates are susceptible to attack, then auto-updating can lead to a compromise of the client(s).
Pushing a update to a client that cause damage to the client could have legal risks, and risks to your business' reputation.
If you can find a way to avoid reinventing the wheel, that would be good. See the other answers for suggestions.
I am currently developing a JAVA Linux Daemon and also had the need to implement an auto-update mechanism. I wanted to limit my application to one jar file, and came up with a simple solution:
Pack the updater application in the update itself.
Application: When the application detects a newer version it does the following:
Download update (Zipfile)
Extract Application and ApplicationUpdater (all in the zipfile)
Run updater
ApplicationUpdater: When the updater runs it does the following:
Stop the Application (in my case a daemon via init.d)
Copy the downloaded jar file to overwrite current Application
Start the Application
Cleanup.
Hope it helps someone.
I've recently created update4j which is fully compatible with Java 9's module system.
It will seamlessly start the new version without a restart.
This is a known problem and I recommend against reinventing a wheel - don't write your own hack, just use what other people have already done.
Two situations you need to consider:
App needs to be self-updatable and keep running even during update (server app, embedded apps). Go with OSGi: Bundles or Equinox p2.
App is a desktop app and has an installer. There are many installers with update option. Check installers list.
I've written a Java application that can load plugins at runtime and start using them immediately, inspired by a similar mechanism in jEdit. jEdit is open source so you have the option of looking to see how it works.
The solution uses a custom ClassLoader to load files from the jar. Once they're loaded you can invoke some method from the new jar that will act as its main method. Then the tricky part is making sure you get rid of all references to the old code so that it can be garbage collected. I'm not quite an expert on that part, I've made it work but it wasn't easy.
First way: use tomcat and it's deploy facilities.
Second way: to split application on two parts (functional and update) and let update part replace function part.
Third way: In your server appliction just download new version, then old version releases bound port, then old version runs new version (starts process), then old version sends a request on application port to the new version to delete old version, old version terminates and new version deletes old version. Like this:
This isn't necessarily the best way, but it might work for you.
You can write a bootstrap application (ala the World of Warcraft launcher, if you've played WoW). That bootstrap is responsible for checking for updates.
If an update is available, it will offer it to the user, handle the download, installation, etc.
If the application is up to date, it will allow the user to launch the application
Optionally, you can allow the user to launch the application, even if it isn't up to date
This way you don't have to worry about forcing an exit of your application.
If your application is web based, and if it is important that they have an up to date client, then you can also do version checks while the application runs. You can do them at intervals, while performing normal communication with the server (some or all calls), or both.
For a product I recently worked on, we did version checks upon launch (without a boot strapper app, but before the main window appeared), and during calls to the server. When the client was out of date, we relied on the user to quit manually, but forbid any action against the server.
Please note that I don't know if Java can invoke UI code before you bring up your main window. We were using C#/WPF.
If you build your application using Equinox plugins, you can use the P2 Provisioning System to get a ready-made solution to this problem. This will require the server to restart itself after an update.
I see a security problem when downloading a new jar (etc.), e.g., a man in the middle attack. You always have to sign your downloadable update.
On JAX2015, Adam Bien told about using JGit for updating the binaries.
Sadly I could not find any tutorials.
Source in German.
Adam Bien created the updater see here
I forked it here with some javaFX frontend. I am also working on an automatic signing.

Can I use directly H2O library functions from Java or the only option for H2O is R?

I want to use machine learning algorithms in java. Mahout with hadoop is too slow and weka is not able to work because of large datasize.
So is it possible to call H2O library from Java or any other better option available for java?
What you can do is implement your machine learning algorithms in R, and then call them via command line calls to the underlying system. I found this to be my best option when doing my thesis in Bioinformatics a few years ago.
I remember trying to call the R engine directly from Java using some kind of Java/R integration-library, but decided it was too slow and cumbersome, so I ended up instead writing simple scripts in R, which Java could call via the command line interface.
The downside of this is that slow processes may be hard to track; you might not get any result from an R-operation until it has completed and returned it's status code.
You'll need to write some Java code to issue the R commands, and wait for the response/result from the process, preferably without locking your Java application completely (separate threads, or a background process).
Yes you can. Please see the instructions on the H2O Flow UI pressing the POJO button after Building and Viewing a model. It gives you detailed instructions about how to download your generated model as a java file (POJO) and about how to download the h20 jar file needed to run it. You can get the same instructions pressing the Preview POJO button.

create and display multiple windows simultaneously using javaFX

I'm currently designing a GUI using JavaFX and SceneBulder.
I would like it be composed of several windows, each of which can be hidden, resized, deleted, etc.... in much the same way that is posible in Final Cut Pro 7.
For example: http://www.squarebox.com/legacy/xfer_fcp7.png
I have read various posts and articles (e.g. Angela Caicedo's article for Oracle) about creating apps with multiple windows but none of them seem to address displaying several windows simultaneously and enabling the contents of these separate windows to communicate with each other.
I have read a post which suggests just creating several stages (and therefore windows) in the start method of the main Class. I am tempted to go down this route but am suspicious as it seems crude and I get the sense that this might lead to problems later down the line with regards to getting each window to interact.
Any help or recommendations with regards to design would be appreciated.
Thanks for reading.

Java IDE for working over Remote Desktop

I have recently found out that anything Swing(NetBeans, IDEA) is excruciatingly slow to paint the UI over Remote Desktop(RDP).
Can you guys give me any suggestion for something that will work properly over RDP?
Actually, contrary to everything I've seen - mostly the "Dsun.java2d.noddraw=true", which is mentioned in a number of places, it is actually setting it to false that fixed the drawing issues(for me at least). Go figure.
RDP is optimized for native Windows apps and, regrettably, newer versions of RCP (like Vista/Win7's default RDP) is even more hostile to non-native apps than older (XP/Server 2003) versions. Here's a good link:
http://devnet.jetbrains.net/thread/280673
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4204845
One workaround is to get a screaming fast CPU/graphics board, tons and tons of memory and a super high-speed network connection :)
Another is to:
Select "32-bit true color" in your Terminal Services settings
Select "Modem"
Reduce screen resolution (heck, use 1024x768 if possible)
Here are some additional tips:
http://www.codinghorror.com/blog/2006/04/remote-desktop-tips-and-tricks.html
Try setting "Dsun.java2d.noddraw=true"
http://ubuntuforums.org/archive/index.php/t-1129187.html
http://www.mindfiresolutions.com/Solving-DIRECT-DRAW-ddraw-problems-in-Java-Swing-730.php
I am launching a java swing application from Linux, and display it as a Windows frame thanks to MobaXterm.
If you haven't done it already, please have a look at the following documentation :
https://docs.oracle.com/javase/8/docs/technotes/guides/2d/flags.html
Using -Dsun.java2d.noddraw=true did not fixed my issue, but setting xrender to true did.
So here's the code I used on Linux :
export _JAVA_OPTIONS='-Dsun.java2d.xrender=true'
java -jar my_java_application.jar
Maybe it's not only Swing that paints slow over Remote Desktop. However, Eclipse is based on SWT, based on native widgets, so it is not Swing.
You should give JavaWIDE a try. It is an IDE designed for access to a JDK without it installed on a system, with a built-in storage system so you just need access to the internet. It's not exactly a program for accessing everything on the computer but it will do a good job with your programming. It may take a while however, as the compiling is done on a separate server.

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