Jbang exploration

Installing jbang

ASDF is what i used (works in linux and mac)

Basics

Minimum requirement Java 8
argument to jbang
- Kotlin and groovy are experimental

Extension	operation
.java	Compile the java
.jsh	Jshell
.md	Java code inside markdown
Folder	Main.java file executed

Get started
```
jbang Sample.java
```

Sample.java

public class Sample {
    public static void main(String[] args) {
        System.out.println("Hello, this is a simple Java program!");
    }
}

Managing Java version

Adopt JDK will be used
List jdk installed in the system
```
jbang jdk list
```
Install particular java version
```
jbang jdk install 14
```
List all the available version by jbang
```
jbang jdk list --available
```
Set default jdk version
```
jbang jdk default 17
```
Uninstall particular version
```
jbang jdk uninstall 17
```
JDK home path
```
jbang jdk home
```

Install java from existing path

jbang jdk install 17 <PATH>
jbang jdk install 17 `sdk home java 17.0.4.1-tem`

Environment variable details
```
jbang jdk java-env
```

Simple example

java init --template=cli hello.java

JFX

Let's look into few examples

    //JAVA 21+
//DEPS org.openjfx:javafx-controls:21:${os.detected.jfxname}
//DEPS org.openjfx:javafx-graphics:21:${os.detected.jfxname}
//RUNTIME_OPTIONS --enable-native-access=javafx.graphics
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;


public class jfx extends Application {

    @Override
    public void start(Stage stage) {
        String javaVersion = System.getProperty("java.version");
        String javafxVersion = System.getProperty("javafx.version");
        Label l = new Label("Hello, JavaFX " + javafxVersion + ", running on Java " + javaVersion + ".");
        Scene scene = new Scene(new StackPane(l), 640, 480);
        stage.setScene(scene);
        stage.show();
    }

    public static void main(String[] args) {
        launch();
    }

}

Jbang edit

jbang edit myfile.java

For Emacs/Vim (in sandbox mode), For editor that doesn't support jbang
```
jbang edit -b myfile.java
```
Live editing
```
jbang edit --live
```

Jshell integration

Simple jsh file

// Import necessary classes
import java.util.ArrayList;

// Create a list and add elements
ArrayList<String> fruits = new ArrayList<>();
fruits.add("Apple");
fruits.add("Banana");
fruits.add("Cherry");

// Print the list
System.out.println("Fruits: " + fruits);

// Iterate over the list
for (String fruit : fruits) {
    System.out.println(fruit);
}

Execute the above script using
```
jbang Sample.jsh
```
We can spawn a interactive shell using the following command
```
jbang --interactive Sample.jsh
```

Java debugging

jbang --debug hello.java

attach with jdb
```
jdb -attach IP_ADDRESS:PORT
```

Export

Gradle

jbang export gradle --group org.acme --artifact myapp --version 1.0.0-SNAPSHOT hello.java

Maven

jbang export maven --group org.acme --artifact myapp --version 1.0.0-SNAPSHOT hello.java

Java Flight Recorder

jbang --jfr myapp.java

Want more

https://www.jbang.dev/try/ (run it in the browser)
Check their docs
It can also generate Native code using GraalVM.