{{tag>Java Langage CA}}

= Langage Groovy

Voir aussi :
 * https://developers.redhat.com/articles/2023/07/06/how-use-debezium-smt-groovy-filter-routing-events


== Hello world

<code groovy>
#! /usr/bin/env groovy

/* 
This is an example
*/

println "Hello World !"
</code>


== Importer une class

<code groovy>
/*
#from java.util import Date
#from java.text import SimpleDateFormat
*/

import java.util.Date
import java.text.SimpleDateFormat
</code>


== Fichier java .class

''test.groovy''
<code groovy>
#! /usr/bin/env groovy

println "Test1"

class echo1 {
        def name;
        String hello() {
                println "Test2"
                return name
        }
}

</code>

<code bash>
groovyc test.groovy 
</code>

<code ->
$ strings test.class |grep -i test
test
test.groovy
Ltest;
Test1

$ file *.class
echo1.class: compiled Java class data, version 49.0 (Java 1.5)
test.class:  compiled Java class data, version 49.0 (Java 1.5)
</code>

<code ->
$ groovy --classpath=. test
Test1
$ groovy --classpath=. test.groovy
Test1
</code>




== Pb 



=== Pb WARNING: An illegal reflective access operation has occurred

<code ->
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.codehaus.groovy.reflection.CachedClass (file:/usr/share/groovy/lib/groovy-2.4.21.jar) to method java.lang.Object.finalize()
WARNING: Please consider reporting this to the maintainers of org.codehaus.groovy.reflection.CachedClass
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
</code>


=== Pb Error: Could not find or load main class test

<code ->
$ java -cp . test
Error: Could not find or load main class test
Caused by: java.lang.NoClassDefFoundError: groovy/lang/Script
</code>


==== Solution

<code bash>
java -cp /usr/share/groovy/lib/groovy-2.4.21.jar:$PWD test
</code>


=== Pb Error: Main method not found in class xxx

<code bash>
$ java -cp /usr/share/groovy/lib/groovy-2.4.21.jar:$PWD echo1
Error: Main method not found in class echo1, please define the main method as:
   public static void main(String[] args)
or a JavaFX application class must extend javafx.application.Application
</code>

==== Solution

Voir : https://www.yawintutor.com/main-method-not-found-javafx-application-class/

''test.groovy''
<code groovy>
#! /usr/bin/env groovy

package com.plop;

public class Hello {
        public static void main(String[] args) {
                System.out.println("Hello World");
        }
}
</code>

<code bash>
java -cp /usr/share/groovy/lib/groovy-2.4.21.jar:$PWD com/plop/Hello
</code>