Hi there AppWorks fans,

Welcome to a new installment of AppWorks tips.

The post from last week (the AWP SDK) gave me a deeper insight on Java itself; It also exposed an interesting tool I just want to share in this post…It can benefit anyone who requires to work with Java on the AppWorks platform.

Let get right into it…

How did I even bump into this tool? Well, from last week’s post I tried to call specific Java classes to see what value they bring in my advantage. The classes ran on my local machine via my IDE, but I was wondering what the result of some classes would be running it on my remote AWP VM!? I could just generate a JAR (via maven), upload it to the VM and run the JAR, but I was looking for more editable approach! After Googling, I found a simple solution via the jshell tool delivered with Java itself.

Have yourself a first look; Start you AWP VM (with Java 11), login via MobaXTerm and give this command: /usr/lib/jvm/java-11-openjdk-11.0.16.0.8-1.el8_6.x86_64/bin/jshell

Learn the basics of jshell here

After you get yourself familiar with the tool, let’s do a call like this: EIBProperties.getProperties().forEach((key, value) -> {System.out.printf("key: %s; value: %s%n", key, value);});

Hmmm…That’s an error for missing the import for EIBProperties. So, let’s import import com.eibus.util.system.EIBProperties;. That’s another error on finding the package!?

So, can we call jshell with a class-path option? Yes, we can! Let’s start JShell like this:

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/usr/lib/jvm/java-11-openjdk-11.0.16.0.8-1.el8_6.x86_64/bin/jshell --class-path /opt/opentext/AppWorksPlatform/defaultInst/components/basicutil/basicutil.jar`

You can exit JShell via: /exit

Once you’re in JShell again, import the package, and run our Java-code-line…Just like this:

Niceee! 🤗

Can we also break lines? You mean like this:

O-boy-O-boy…Nice tool…

Can we also read a Java source file and run it? Well, make sure to upload a Java source file (to your home directory on the VM) like for example Simple.java with this content:

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class Simple{  
    public static void main(String args[]){  
        System.out.println("Hello Java");  
    }  
}

In JShell, you can open the file with: /open ~/TestApp.java. Do a verification with /types or /list in JShell itself. To run that main method you can do a call like this: Simple.main(null)
You can even instantiate the ‘Simple’ object Simple simple = new Simple(); and call main from the instance: simple.main(new String[0]).

It’s a party! 🎉 I leave the rest for you to explore…

That’s a nice and quick post…A “DONE” as I may say. It’s always interesting to see how tools can bring actions to your own advantage. Play with it and learn yourself a bit of Java. Have a great weekend…cheers.

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