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![hello.java: class hello { public static void main(String... args) throws Exception { System.out.println( "Hello " + ((args.length>0)?args[0]:"java")); } } Java 1-9 Manually need to set classpath to use 3rd party dependencies 2 steps that should be one!](https://image.slidesharecdn.com/jbangdntt5-29-20-200529144058/75/jbang-Unleash-the-power-of-Java-for-shell-scripting-8-2048.jpg)
![class hello { public static void main(String... args) throws Exception { System.out.println( "Hello " + ((args.length>0)?args[0]:"java")); } } Java 10+ Module system but still manually configure classpath](https://image.slidesharecdn.com/jbangdntt5-29-20-200529144058/75/jbang-Unleash-the-power-of-Java-for-shell-scripting-10-2048.jpg)
![hello: #!/usr/bin/env java --source 11 class hello { public static void main(String... args) throws Exception { System.out.println( "Hello " + ((args.length>0)?args[0]:"jbang")); } } Java 11+ Cannot be called .java #! works but must have --source 11 Breaks every IDE :(](https://image.slidesharecdn.com/jbangdntt5-29-20-200529144058/75/jbang-Unleash-the-power-of-Java-for-shell-scripting-11-2048.jpg)
![hello.java: //usr/bin/env jbang "$0" "$@" ; exit $? //DEPS com.github.lalyos:jfiglet:0.0.8 import com.github.lalyos.jfiglet.FigletFont; class hello { public static void main(String... args) throws Exception { System.out.println(FigletFont.convertOneLine( "Hello " + ((args.length>0)?args[0]:"jbang"))); } } Valid Java AND shell script External Dependency management Compile and run in one!](https://image.slidesharecdn.com/jbangdntt5-29-20-200529144058/75/jbang-Unleash-the-power-of-Java-for-shell-scripting-15-2048.jpg)
![hello.java: //usr/bin/env jbang "$0" "$@" ; exit $? //DEPS https://github.com/lalyos/jfiglet import com.github.lalyos.jfiglet.FigletFont; class hello { public static void main(String... args) throws Exception { System.out.println(FigletFont.convertOneLine( "Hello " + ((args.length>0)?args[0]:"jbang"))); } } Use github repos as dependencies (snapshot, branches & tags)](https://image.slidesharecdn.com/jbangdntt5-29-20-200529144058/75/jbang-Unleash-the-power-of-Java-for-shell-scripting-26-2048.jpg)
![//usr/bin/env jbang "$0" "$@" ; exit $? //JAVAC_OPTIONS --enable-preview -source 14 //JAVA_OPTIONS --enable-preview import static java.lang.System.*; public class records { record Point(int x, int y) {} public static void main(String[] args) { var p = new Point(2,4); out.println(p); } } Try out latest greatest preview features](https://image.slidesharecdn.com/jbangdntt5-29-20-200529144058/75/jbang-Unleash-the-power-of-Java-for-shell-scripting-28-2048.jpg)
![hello.jsh: //usr/bin/env jbang "$0" "$@" ; exit $? //DEPS com.github.lalyos:jfiglet:0.0.8 import com.github.lalyos.jfiglet.FigletFont; System.out.println(FigletFont.convertOneLine( "Hello " + ((args.length>0)?args[0]:"jbang"))); /exit jshell ! No main()! arguments! Executable jshell script!](https://image.slidesharecdn.com/jbangdntt5-29-20-200529144058/75/jbang-Unleash-the-power-of-Java-for-shell-scripting-29-2048.jpg)
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jbang: Unleash the power of Java for shell scripting
The document discusses using Java as a powerful scripting language, highlighting its relevance among popular languages like Kotlin and Groovy. It explains features and tools available in Java for scripting, such as external dependencies, executable scripts, and IDE support, while simplifying the setup process with JBang. Furthermore, it encourages developers to leverage JBang for automating tasks and developing quick scripts, showcasing various examples and dependencies management options.
jbang: Unleash the power of Java for shell scripting
- 1. Unleash the powerof Java for shell scripting by Max Rydahl Andersen @maxandersen https://jbang.dev
- 3. Why Java asa scripting language makes sense Top #1-#2 language in the world! Kotlin and Groovy does it, why not Java ? Content assist and refactoring in all major IDE’s and text editors Debugging! Monitoring! Recent Java language features (var, <>, lambda, text blocks, …) Streams and more system level access in JDK Massive ecosystem of 3rd party dependencies BUT Maven, Gradle, etc. should NOT be required to start
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- 7. “Everything should bemade as simple as possible, but not simpler” - (maybe) Albert Einstein
- 8. hello.java: class hello { publicstatic void main(String... args) throws Exception { System.out.println( "Hello " + ((args.length>0)?args[0]:"java")); } } Java 1-9 Manually need to set classpath to use 3rd party dependencies 2 steps that should be one!
- 9. Java 9 (introducesjshell) hello.jsh: System.out.println("Hello); Awesome! No main! No way to handle arguments! Kinda Breaks in IDE’s
- 10. class hello { publicstatic void main(String... args) throws Exception { System.out.println( "Hello " + ((args.length>0)?args[0]:"java")); } } Java 10+ Module system but still manually configure classpath
- 11. hello: #!/usr/bin/env java --source11 class hello { public static void main(String... args) throws Exception { System.out.println( "Hello " + ((args.length>0)?args[0]:"jbang")); } } Java 11+ Cannot be called .java #! works but must have --source 11 Breaks every IDE :(
- 12. Java 1-8 Java10 Java 11 1 Compile & build in one 2 External Dependencies 3 Executable scripts (./hello) 5 (Easy) Debugging 4 IDE support
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- 15. hello.java: //usr/bin/env jbang "$0""$@" ; exit $? //DEPS com.github.lalyos:jfiglet:0.0.8 import com.github.lalyos.jfiglet.FigletFont; class hello { public static void main(String... args) throws Exception { System.out.println(FigletFont.convertOneLine( "Hello " + ((args.length>0)?args[0]:"jbang"))); } } Valid Java AND shell script External Dependency management Compile and run in one!
- 20. Yes - TheyWork too!
- 22. Java 1-8 Java10 Java 11 1 Compile & build in one 2 External Dependencies 3 Executable scripts (./hello) 5 (Easy) Debugging 4 IDE support
- 23. ...but there ismore...
- 24. Init for gettingstarted quickly
- 25. Caching for fastre-runs
- 26. hello.java: //usr/bin/env jbang "$0""$@" ; exit $? //DEPS https://github.com/lalyos/jfiglet import com.github.lalyos.jfiglet.FigletFont; class hello { public static void main(String... args) throws Exception { System.out.println(FigletFont.convertOneLine( "Hello " + ((args.length>0)?args[0]:"jbang"))); } } Use github repos as dependencies (snapshot, branches & tags)
- 27. //REPOS jboss,google //REPOS acme=https://maven.acme.local/maven @GrabResolver("mavenCentral")// (2) @GrabResolver(name='acme', root='https://maven.acme.local/maven') @Grapes({ // (3) @Grab(group="org.codehaus.groovy", module="groovy", version="2.5.8"), // (4) @Grab(module = "log4j", group = "log4j", version = "1.2.17") }) Easy add common maven repositories Use custom incl. Secured repoistories Use Groovy style @Grab
- 28. //usr/bin/env jbang "$0""$@" ; exit $? //JAVAC_OPTIONS --enable-preview -source 14 //JAVA_OPTIONS --enable-preview import static java.lang.System.*; public class records { record Point(int x, int y) {} public static void main(String[] args) { var p = new Point(2,4); out.println(p); } } Try out latest greatest preview features
- 29. hello.jsh: //usr/bin/env jbang "$0""$@" ; exit $? //DEPS com.github.lalyos:jfiglet:0.0.8 import com.github.lalyos.jfiglet.FigletFont; System.out.println(FigletFont.convertOneLine( "Hello " + ((args.length>0)?args[0]:"jbang"))); /exit jshell ! No main()! arguments! Executable jshell script!
- 30. Write kubectl extensions kubectlexample pod list ________________________________________________________________ | Pod Name | namespace | |===============================================================| | coredns-6955765f44-f966p | kube-system | | coredns-6955765f44-xnzbg | kube-system | | etcd-kind-control-plane | kube-system | | kindnet-cznll | kube-system | | kube-apiserver-kind-control-plane | kube-system | | kube-controller-manager-kind-control-plane| kube-system | | kube-proxy-tw9cb | kube-system | | kube-scheduler-kind-control-plane | kube-system | | local-path-provisioner-7745554f7f-gk5j9 | local-path-storage| See how at https://github.com/jbangdev/k8s-cli-java
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- 32. How do Iget it ? https://jbang.dev/download Windows Linux Mac Docker/Container Github Action
- 33. Go Use JBang! ●Use it for your automation needs ● One-off scripts for fixing things ● When trying out new apis ● In docs showing how to use your api ● In issues when making a reproducer ● When teaching newcomers to java
- 34. Thanks! https://jbang.dev @maxandersen Tweet your gist/githubjbang script with a #jbang If done in the next week I’ll add you to the wall of contributor fame!