Add the com.google.guava as a dependency.

build.gradle

@@ -18,6 +18,7 @@ repositories {
 }
 
 dependencies {
+  implementation 'com.google.guava:guava:32.1.2-jre'
   // mandatory dependencies for using Spock
   implementation platform('org.apache.groovy:groovy-bom:4.0.15')
   implementation 'org.apache.groovy:groovy'

pom.xml

@@ -12,6 +12,8 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
     <groovy.version>4.0.15</groovy.version>
+    <maven.compiler.source>17</maven.compiler.source>
+    <maven.compiler.target>17</maven.compiler.target>
   </properties>
 
   <build>
@@ -77,6 +79,11 @@
   </dependencyManagement>
 
   <dependencies>
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava</artifactId>
+      <version>32.1.2-jre</version>
+    </dependency>
     <!-- Mandatory dependencies for using Spock -->
     <dependency>
       <groupId>org.spockframework</groupId>