Fix compatibility on jdk > 21

pom.xml

@@ -66,6 +66,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.source>17</maven.compiler.source>
         <maven.compiler.target>17</maven.compiler.target>
+        <maven.compiler.release>17</maven.compiler.release>
 
         <fabric8.version>6.12.0</fabric8.version>
         <log4j.version>2.17.2</log4j.version>

test-frame-common/src/main/java/io/skodjob/testframe/executor/Exec.java

@@ -167,6 +167,8 @@ public static ExecResult exec(String input, List<String> command, int timeout, b
     }
 
     /**
+     * Method executes external command
+     *
      * @param input       input
      * @param command     command
      * @param timeout     timeout for command

test-frame-common/src/main/java/io/skodjob/testframe/executor/ExecBuilder.java

@@ -22,6 +22,11 @@ public class ExecBuilder {
     private boolean logToOutput;
     private boolean throwErrors;
 
+    /**
+     * Constructor
+     */
+    public ExecBuilder() { }
+
     /**
      * Sets the command to execute.
      *

test-frame-common/src/main/java/io/skodjob/testframe/listeners/ResourceManagerCleanerExtension.java

@@ -19,6 +19,10 @@
  */
 public class ResourceManagerCleanerExtension implements AfterAllCallback, AfterEachCallback {
 
+    private ResourceManagerCleanerExtension() {
+        // Private constructor to prevent instantiation
+    }
+
     /**
      * Enables ResourceManagerCleanerExtension for after All callback
      * @param extensionContext context

test-frame-common/src/main/java/io/skodjob/testframe/listeners/ResourceManagerExtension.java

@@ -17,6 +17,10 @@
 public class ResourceManagerExtension
         implements BeforeAllCallback, BeforeEachCallback, AfterAllCallback, AfterEachCallback {
 
+    private ResourceManagerExtension() {
+        // Private constructor to prevent instantiation
+    }
+
     @Override
     public void beforeAll(ExtensionContext extensionContext) {
         KubeResourceManager.getInstance();

test-frame-common/src/main/java/io/skodjob/testframe/listeners/TestVisualSeparatorExtension.java

@@ -16,6 +16,11 @@
  */
 public class TestVisualSeparatorExtension implements BeforeEachCallback, AfterEachCallback {
     private final Logger logger = LogManager.getLogger(TestVisualSeparatorExtension.class);
+
+    private TestVisualSeparatorExtension() {
+        // Private constructor to prevent instantiation
+    }
+
     @Override
     public void beforeEach(ExtensionContext extensionContext) {
         LoggerUtils.logSeparator();

test-frame-common/src/main/java/io/skodjob/testframe/resources/KubeResourceManager.java

@@ -47,6 +47,10 @@ public class KubeResourceManager {
     private List<Consumer<HasMetadata>> createCallbacks = new LinkedList<>();
     private List<Consumer<HasMetadata>> deleteCallbacks = new LinkedList<>();
 
+    private KubeResourceManager() {
+        // Private constructor to prevent instantiation
+    }
+
     /**
      * Retrieves the singleton instance of KubeResourceManager.
      * @return The singleton instance of KubeResourceManager.

test-frame-common/src/main/java/io/skodjob/testframe/wait/Wait.java

@@ -25,6 +25,10 @@
 public class Wait {
     private static final Logger LOGGER = LogManager.getLogger(Wait.class);
 
+    private Wait() {
+        // Private constructor to prevent instantiation
+    }
+
     /**
      * For every poll (happening once each {@code pollIntervalMs}) checks if supplier {@code ready} is true.
      * If yes, the wait is closed. Otherwise, waits another {@code pollIntervalMs} and tries again.

test-frame-kubernetes/src/main/java/io/skodjob/testframe/installation/InstallationMethod.java

@@ -8,6 +8,11 @@
  * Abstract class containing methods that can be implemented in particular setup classes based on the installation type.
  */
 public abstract class InstallationMethod {
+
+    private InstallationMethod() {
+        // Private constructor to prevent instantiation
+    }
+
     /**
      * Deploy deployment/operator abstract method
      */