Update the build configuration to make the JAR file.

build.gradle

@@ -1,11 +1,21 @@
 plugins {
     id('groovy')
+    id('application')
+    id 'com.github.johnrengelman.shadow' version '7.1.2'
 }
 
 version = "1.0"
 description = "simple-jbdd is a simple BDD testing framework for Java."
 
-// Spock works with Java 1.8 and above
+application {
+    mainClassName = 'space.kklochko.simple_jbdd.Main'
+}
+
+shadowJar {
+    mergeServiceFiles()
+    minimize()
+}
+
 java {
     toolchain {
         languageVersion.set(JavaLanguageVersion.of(17))

pom.xml

@@ -18,6 +18,32 @@
 
   <build>
     <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-jar-plugin</artifactId>
+        <version>3.2.2</version>
+        <configuration>
+          <archive>
+            <manifest>
+              <mainClass>space.kklochko.simple_jbdd.Main</mainClass>
+              <addClasspath>true</addClasspath>
+            </manifest>
+          </archive>
+        </configuration>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-shade-plugin</artifactId>
+        <version>3.4.1</version>
+        <executions>
+          <execution>
+            <phase>package</phase>
+            <goals>
+              <goal>shade</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
       <!-- Mandatory plugins for using Spock -->
       <plugin>
         <!-- The gmavenplus plugin is used to compile Groovy code. To learn more about this plugin,
@@ -124,16 +150,5 @@
       <version>2.2</version>
       <scope>test</scope>
     </dependency>
-    <!-- Dependencies used by examples in this project (not required for using Spock) -->
-    <dependency>
-      <groupId>com.h2database</groupId>
-      <artifactId>h2</artifactId>
-      <version>2.2.222</version>
-    </dependency>
-    <dependency>
-      <groupId>org.apache.groovy</groupId>
-      <artifactId>groovy-sql</artifactId>
-      <version>${groovy.version}</version>
-    </dependency>
   </dependencies>
 </project>