style: use bounded wildcards for private, and static methods

src/components/src/main/java/org/apache/jmeter/extractor/RegexExtractor.java

@@ -313,7 +313,7 @@ private List<java.util.regex.MatchResult> processMatches(
     }
 
     private static int matchStrings(int matchNumber, Perl5Matcher matcher,
-            Pattern pattern, List<MatchResult> matches, int found,
+            Pattern pattern, List<? super MatchResult> matches, int found,
             String inputString) {
         PatternMatcherInput input = new PatternMatcherInput(inputString);
         while (matchNumber <=0 || found != matchNumber) {
@@ -329,7 +329,7 @@ private static int matchStrings(int matchNumber, Perl5Matcher matcher,
     }
 
     private static int matchStrings(int matchNumber, java.util.regex.Pattern pattern,
-            List<java.util.regex.MatchResult> matches, int found,
+            List<? super java.util.regex.MatchResult> matches, int found,
             String inputString) {
         Matcher matcher = pattern.matcher(inputString);
         while (matchNumber <=0 || found != matchNumber) {
@@ -513,7 +513,7 @@ private void initTemplate() {
      *            the entry number in the list
      * @return MatchResult
      */
-    private static MatchResult getCorrectMatch(List<MatchResult> matches, int entry) {
+    private static MatchResult getCorrectMatch(List<? extends MatchResult> matches, int entry) {
         int matchSize = matches.size();
 
         if (matchSize <= 0 || entry > matchSize){
@@ -528,7 +528,7 @@ private static MatchResult getCorrectMatch(List<MatchResult> matches, int entry)
         return matches.get(entry - 1);
     }
 
-    private static java.util.regex.MatchResult getCorrectMatchJavaRegex(List<java.util.regex.MatchResult> matches, int entry) {
+    private static java.util.regex.MatchResult getCorrectMatchJavaRegex(List<? extends java.util.regex.MatchResult> matches, int entry) {
         int matchSize = matches.size();
 
         if (matchSize <= 0 || entry > matchSize){

src/components/src/main/java/org/apache/jmeter/extractor/XPath2Extractor.java

@@ -222,7 +222,7 @@ public void setFragment(boolean selected) {
      * @throws SaxonApiException
      * @throws FactoryConfigurationError
      */
-    private void getValuesForXPath(String query, List<String> matchStrings, int matchNumber, String responseData)
+    private void getValuesForXPath(String query, List<? super String> matchStrings, int matchNumber, String responseData)
             throws SaxonApiException, FactoryConfigurationError {
         XPathUtil.putValuesForXPathInListUsingSaxon(responseData, query, matchStrings, getFragment(), matchNumber, getNamespaces());
     }

src/components/src/main/java/org/apache/jmeter/extractor/XPathExtractor.java

@@ -318,7 +318,7 @@ private Document parseResponse(String unicodeData)
      *
      * @throws TransformerException
      */
-    private void getValuesForXPath(Document d,String query, List<String> matchStrings, int matchNumber)
+    private void getValuesForXPath(Document d,String query, List<? super String> matchStrings, int matchNumber)
         throws TransformerException {
         XPathUtil.putValuesForXPathInList(d, query, matchStrings, getFragment(), matchNumber);
     }

src/components/src/main/java/org/apache/jmeter/visualizers/RenderAsXML.java

@@ -152,7 +152,7 @@ private void expandAll(TreePath parent) {
         }
 
         @SuppressWarnings("JdkObsolete")
-        private static void applyToChildren(TreePath parent, Consumer<TreePath> method) {
+        private static void applyToChildren(TreePath parent, Consumer<? super TreePath> method) {
             TreeNode node = (TreeNode) parent.getLastPathComponent();
             Enumeration<?> e = node.children();
             while (e.hasMoreElements()) {

src/components/src/main/java/org/apache/jmeter/visualizers/ViewResultsFullVisualizer.java

@@ -236,7 +236,7 @@ private Object getSelectedObject() {
 
     private static TreePath checkExpandedOrSelected(List<TreeNode> path,
             Object item, Object oldSelectedObject,
-            Set<Object> oldExpandedObjects, Set<TreePath> newExpandedPaths,
+            Set<Object> oldExpandedObjects, Set<? super TreePath> newExpandedPaths,
             TreePath defaultPath) {
         TreePath result = defaultPath;
         if (oldSelectedObject == item) {
@@ -250,7 +250,7 @@ private static TreePath checkExpandedOrSelected(List<TreeNode> path,
 
     private static TreePath checkExpandedOrSelected(List<TreeNode> path,
             Object item, Object oldSelectedObject,
-            Set<Object> oldExpandedObjects, Set<TreePath> newExpandedPaths,
+            Set<Object> oldExpandedObjects, Set<? super TreePath> newExpandedPaths,
             TreePath defaultPath, DefaultMutableTreeNode extensionNode) {
         TreePath result = defaultPath;
         if (oldSelectedObject == item) {
@@ -279,7 +279,7 @@ private static Set<Object> extractExpandedObjects(final Enumeration<TreePath> ex
 
     private TreePath addSubResults(DefaultMutableTreeNode currNode,
             SampleResult res, List<TreeNode> path, Object selectedObject,
-            Set<Object> oldExpandedObjects, Set<TreePath> newExpandedPaths) {
+            Set<Object> oldExpandedObjects, Set<? super TreePath> newExpandedPaths) {
         SampleResult[] subResults = res.getSubResults();
 
         int leafIndex = 0;

src/components/src/main/java/org/apache/jmeter/visualizers/backend/graphite/PickleGraphiteMetricsSender.java

@@ -55,7 +55,7 @@ class PickleGraphiteMetricsSender extends AbstractGraphiteMetricsSender {
     private List<MetricTuple> metrics = new ArrayList<>();
 
     private SocketConnectionInfos socketConnectionInfos;
-    private GenericKeyedObjectPool<SocketConnectionInfos, SocketOutputStream> socketOutputStreamPool;
+    private GenericKeyedObjectPool<? super SocketConnectionInfos, SocketOutputStream> socketOutputStreamPool;
     private String prefix;
 
     PickleGraphiteMetricsSender() {
@@ -79,7 +79,7 @@ public void setup(String graphiteHost, int graphitePort, String prefix) {
 
     /** Setup used for testing, or if explicit customisation is required. */
     public void setup(SocketConnectionInfos socketConnectionInfos,
-                      GenericKeyedObjectPool<SocketConnectionInfos, SocketOutputStream> socketOutputStreamPool,
+                      GenericKeyedObjectPool<? super SocketConnectionInfos, SocketOutputStream> socketOutputStreamPool,
                       String prefix) {
         this.socketConnectionInfos = socketConnectionInfos;
         this.socketOutputStreamPool = socketOutputStreamPool;

src/components/src/main/java/org/apache/jmeter/visualizers/backend/graphite/TextGraphiteMetricsSender.java

@@ -39,7 +39,7 @@ class TextGraphiteMetricsSender extends AbstractGraphiteMetricsSender {
     private List<MetricTuple> metrics = new ArrayList<>();
 
     private SocketConnectionInfos socketConnectionInfos;
-    private GenericKeyedObjectPool<SocketConnectionInfos, SocketOutputStream> socketOutputStreamPool;
+    private GenericKeyedObjectPool<? super SocketConnectionInfos, SocketOutputStream> socketOutputStreamPool;
     private String prefix;
 
     TextGraphiteMetricsSender() {
@@ -63,7 +63,7 @@ public void setup(String graphiteHost, int graphitePort, String prefix) {
 
     /** Setup used for testing, or if explicit customisation is required. */
     public void setup(SocketConnectionInfos socketConnectionInfos,
-                      GenericKeyedObjectPool<SocketConnectionInfos, SocketOutputStream> socketOutputStreamPool,
+                      GenericKeyedObjectPool<? super SocketConnectionInfos, SocketOutputStream> socketOutputStreamPool,
                       String prefix) {
         this.socketConnectionInfos = socketConnectionInfos;
         this.socketOutputStreamPool = socketOutputStreamPool;

src/core/src/main/java/org/apache/jmeter/JMeter.java

@@ -1187,7 +1187,7 @@ public ListenToTest(RunMode runMode, boolean remoteStop, ReportGenerator reportG
             this.reportGenerator = reportGenerator;
         }
 
-        public void setStartedRemoteEngines(List<JMeterEngine> engines) {
+        public void setStartedRemoteEngines(List<? extends JMeterEngine> engines) {
             if (runMode != RunMode.REMOTE) {
                 throw new IllegalArgumentException("This method should only be called in RunMode.REMOTE");
             }
@@ -1355,7 +1355,7 @@ public static boolean isNonGUI(){
         return "true".equals(System.getProperty(JMeter.JMETER_NON_GUI)); //$NON-NLS-1$
     }
 
-    private static void startUdpDdaemon(final List<JMeterEngine> engines) {
+    private static void startUdpDdaemon(final List<? extends JMeterEngine> engines) {
         int port = JMeterUtils.getPropDefault("jmeterengine.nongui.port", UDP_PORT_DEFAULT); // $NON-NLS-1$
         int maxPort = JMeterUtils.getPropDefault("jmeterengine.nongui.maxport", 4455); // $NON-NLS-1$
         if (port > 1000){
@@ -1375,7 +1375,7 @@ public void run() {
         }
     }
 
-    private static void waitForSignals(final List<JMeterEngine> engines, DatagramSocket socket) {
+    private static void waitForSignals(final List<? extends JMeterEngine> engines, DatagramSocket socket) {
         byte[] buf = new byte[80];
         System.out.println("Waiting for possible Shutdown/StopTestNow/HeapDump/ThreadDump message on port "+socket.getLocalPort());//NOSONAR
         DatagramPacket request = new DatagramPacket(buf, buf.length);

src/core/src/main/java/org/apache/jmeter/config/gui/ArgumentsPanel.java

@@ -108,7 +108,7 @@ public class ArgumentsPanel extends AbstractConfigGui implements ActionListener
     /** Disable buttons :Detail, Add, Add from Clipboard, Delete, Up and Down*/
     private final boolean disableButtons;
 
-    private final Function<String[], Argument> argCreator;
+    private final Function<String[], ? extends Argument> argCreator;
 
     /** Command for adding a row to the table. */
     private static final String ADD = "add"; // $NON-NLS-1$
@@ -250,7 +250,7 @@ public ArgumentsPanel(String label, Color bkg, boolean enableUpDown, boolean sta
      * @param argCreator function to create {@link Argument}s from Strings taken from clipboard
      */
     public ArgumentsPanel(String label, Color bkg, boolean enableUpDown, boolean standalone, ObjectTableModel model,
-            boolean disableButtons, Function<String[], Argument> argCreator) {
+            boolean disableButtons, Function<String[], ? extends Argument> argCreator) {
         tableLabel = new JLabel(label);
         this.enableUpDown = enableUpDown;
         this.disableButtons = disableButtons;

src/core/src/main/java/org/apache/jmeter/engine/StandardJMeterEngine.java

@@ -237,7 +237,7 @@ private static void removeThreadGroups(List<?> elements) {
         }
     }
 
-    private void notifyTestListenersOfStart(SearchByClass<TestStateListener> testListeners) {
+    private void notifyTestListenersOfStart(SearchByClass<? extends TestStateListener> testListeners) {
         for (TestStateListener tl : testListeners.getSearchResults()) {
             if (tl instanceof TestBean) {
                 TestBeanHelper.prepare((TestElement) tl);
@@ -250,7 +250,7 @@ private void notifyTestListenersOfStart(SearchByClass<TestStateListener> testLis
         }
     }
 
-    private void notifyTestListenersOfEnd(SearchByClass<TestStateListener> testListeners) {
+    private void notifyTestListenersOfEnd(SearchByClass<? extends TestStateListener> testListeners) {
         log.info("Notifying test listeners of end of test");
         for (TestStateListener tl : testListeners.getSearchResults()) {
             try {

src/core/src/main/java/org/apache/jmeter/engine/util/ValueReplacer.java

@@ -81,7 +81,7 @@ public void replaceValues(TestElement el) throws InvalidVariableException {
         setProperties(el, newProps);
     }
 
-    private static void setProperties(TestElement el, Collection<JMeterProperty> newProps) {
+    private static void setProperties(TestElement el, Collection<? extends JMeterProperty> newProps) {
         el.clear();
         for (JMeterProperty jmp : newProps) {
             el.setProperty(jmp);

src/core/src/main/java/org/apache/jmeter/gui/GlobalUndoableEdit.java

@@ -28,9 +28,9 @@ public final class GlobalUndoableEdit extends AbstractUndoableEdit {
     private static final long serialVersionUID = -4964577622742131354L;
     private final UndoHistoryItem item;
     private final UndoHistoryItem previous;
-    private final Consumer<UndoHistoryItem> loader;
+    private final Consumer<? super UndoHistoryItem> loader;
 
-    public GlobalUndoableEdit(UndoHistoryItem item, UndoHistoryItem previous, Consumer<UndoHistoryItem> loader) {
+    public GlobalUndoableEdit(UndoHistoryItem item, UndoHistoryItem previous, Consumer<? super UndoHistoryItem> loader) {
         this.item = item;
         this.previous = previous;
         this.loader = loader;

src/core/src/main/java/org/apache/jmeter/gui/action/ActionRouter.java

@@ -221,7 +221,7 @@ public void removePreActionListener(Class<?> action, ActionListener listener) {
      * @param listener {@link ActionListener}
      * @param actionListeners {@link Set} of {@link ActionListener}
      */
-    private static void removeActionListener(Class<?> action, ActionListener listener, Map<String, Set<ActionListener>> actionListeners) {
+    private static void removeActionListener(Class<?> action, ActionListener listener, Map<? super String, Set<ActionListener>> actionListeners) {
         if (action != null) {
             Set<ActionListener> set = actionListeners.get(action.getName());
             if (set != null) {
@@ -251,7 +251,7 @@ public void addPostActionListener(Class<?> action, ActionListener listener) {
      * @param listener {@link ActionListener}
      * @param actionListeners {@link Set}
      */
-    private static void addActionListener(Class<?> action, ActionListener listener, Map<String, Set<ActionListener>> actionListeners) {
+    private static void addActionListener(Class<?> action, ActionListener listener, Map<? super String, Set<ActionListener>> actionListeners) {
         if (action != null) {
             Set<ActionListener> set = actionListeners.get(action.getName());
             if (set == null) {
@@ -297,7 +297,7 @@ void postActionPerformed(Class<? extends Command> action, ActionEvent e) {
      * @param e {@link ActionEvent}
      * @param actionListeners {@link Set}
      */
-    private static void actionPerformed(Class<? extends Command> action, ActionEvent e, Map<String, Set<ActionListener>> actionListeners) {
+    private static void actionPerformed(Class<? extends Command> action, ActionEvent e, Map<String, ? extends Set<ActionListener>> actionListeners) {
         if (action != null) {
             Set<ActionListener> listenerSet = actionListeners.get(action.getName());
             if (listenerSet != null && !listenerSet.isEmpty()) {

src/core/src/main/java/org/apache/jmeter/gui/action/LoadRecentProject.java

@@ -254,7 +254,7 @@ private static void removeRecentFile(int index) {
      * @param fileLoadRecentFiles List of JMenuItem
      * @return true if at least on JMenuItem is visible
      */
-    public static boolean hasVisibleMenuItem(List<JComponent> fileLoadRecentFiles) {
+    public static boolean hasVisibleMenuItem(List<? extends JComponent> fileLoadRecentFiles) {
         return fileLoadRecentFiles.stream()
                 .anyMatch(JComponent::isVisible);
     }

src/core/src/main/java/org/apache/jmeter/gui/action/Restart.java

@@ -177,7 +177,7 @@ public void run() {
      * @param processArgs arguments to be given to ProcessBuilder
      * @param mainCommand original command line split at spaces
      */
-    private static void processRemainingArgs(List<String> processArgs, String[] mainCommand) {
+    private static void processRemainingArgs(List<? super String> processArgs, String[] mainCommand) {
         boolean paramValue = false;
         StringBuilder partialParamValue = new StringBuilder();
         for (int i = 1; i < mainCommand.length; i++) {

src/core/src/main/java/org/apache/jmeter/gui/action/Save.java

@@ -400,7 +400,7 @@ private static List<File> createBackupFile(File fileToBackup) {
      * @param backupFiles
      *            {@link List} of {@link File}
      */
-    private static int getHighestVersionNumber(Pattern backupPattern, List<File> backupFiles) {
+    private static int getHighestVersionNumber(Pattern backupPattern, List<? extends File> backupFiles) {
         return backupFiles.stream().map(backupFile -> backupPattern.matcher(backupFile.getName()))
                 .filter(matcher -> matcher.find() && matcher.groupCount() > 0)
                 .mapToInt(matcher -> Integer.parseInt(matcher.group(1))).max().orElse(0);
@@ -414,7 +414,7 @@ private static int getHighestVersionNumber(Pattern backupPattern, List<File> bac
      * @return list of files to be deleted based upon properties described
      *         {@link #createBackupFile(File)}
      */
-    private static List<File> backupFilesToDelete(List<File> backupFiles) {
+    private static List<File> backupFilesToDelete(List<? extends File> backupFiles) {
         List<File> filesToDelete = new ArrayList<>();
         if (BACKUP_MAX_HOURS > 0) {
             filesToDelete.addAll(expiredBackupFiles(backupFiles));
@@ -434,7 +434,7 @@ private static List<File> backupFilesToDelete(List<File> backupFiles) {
      * @param backupFiles {@link List} of {@link File} to filter
      * @return {@link List} of {@link File} that are expired
      */
-    private static List<File> expiredBackupFiles(List<File> backupFiles) {
+    private static List<File> expiredBackupFiles(List<? extends File> backupFiles) {
         if (BACKUP_MAX_HOURS > 0) {
             final long expiryMillis = System.currentTimeMillis() - (1L * BACKUP_MAX_HOURS * MS_PER_HOUR);
             return backupFiles.stream().filter(file -> file.lastModified() < expiryMillis).collect(Collectors.toList());

src/core/src/main/java/org/apache/jmeter/gui/action/SearchTreeDialog.java

@@ -387,7 +387,7 @@ private Pair<Integer, Set<JMeterTreeNode>> searchInTree(GuiPackage guiPackage, S
      * @param expand true if we want to expand
      * @param nodes Set of {@link JMeterTreeNode} to mark
      */
-    private static void markConcernedNodes(boolean expand, Set<JMeterTreeNode> nodes) {
+    private static void markConcernedNodes(boolean expand, Set<? extends JMeterTreeNode> nodes) {
         GuiPackage guiInstance = GuiPackage.getInstance();
         JTree jTree = guiInstance.getMainFrame().getTree();
         for (JMeterTreeNode jMeterTreeNode : nodes) {

src/core/src/main/java/org/apache/jmeter/gui/action/template/TemplateManager.java

@@ -188,7 +188,7 @@ public Map<String, Template> parseTemplateFile(File file) throws IOException, SA
      * @param templates Map of {@link Template} referenced by name
      * @param templateNode {@link Node} the xml template node
      */
-    static void parseTemplateNode(Map<String, Template> templates, Node templateNode) {
+    static void parseTemplateNode(Map<? super String, ? super Template> templates, Node templateNode) {
         if (templateNode.getNodeType() == Node.ELEMENT_NODE) {
             Template template = new Template();
             Element element =  (Element) templateNode;

src/core/src/main/java/org/apache/jmeter/gui/tree/JMeterTreeModel.java

@@ -185,7 +185,7 @@ public void removeNodeFromParent(JMeterTreeNode node) {
     }
 
     @SuppressWarnings("JdkObsolete")
-    private static void traverseAndFind(Class<?> type, JMeterTreeNode node, List<JMeterTreeNode> nodeList) {
+    private static void traverseAndFind(Class<?> type, JMeterTreeNode node, List<? super JMeterTreeNode> nodeList) {
         if (type.isInstance(node.getUserObject())) {
             nodeList.add(node);
         }

src/core/src/main/java/org/apache/jmeter/gui/util/JMeterMenuBar.java

@@ -563,7 +563,7 @@ private void makeSearchMenu() {
      * @param menuCreators
      * @param location
      */
-    private static void addPluginsMenuItems(JMenu menu, Collection<MenuCreator> menuCreators, MENU_LOCATION location) {
+    private static void addPluginsMenuItems(JMenu menu, Collection<? extends MenuCreator> menuCreators, MENU_LOCATION location) {
         for (MenuCreator menuCreator : menuCreators) {
             JMenuItem[] menuItems = menuCreator.getMenuItemsAtLocation(location);
             if (menuItems.length != 0) {

src/core/src/main/java/org/apache/jmeter/gui/util/MenuFactory.java

@@ -225,14 +225,14 @@ private static JMeterGUIComponent getGUIComponent(
         return item;
     }
 
-    private static void sortMenus(Collection<List<MenuInfo>> menus) {
+    private static void sortMenus(Collection<? extends List<MenuInfo>> menus) {
         for (List<MenuInfo> menu : menus) {
             menu.sort(Comparator.comparing(MenuInfo::getLabel));
             menu.sort(Comparator.comparingInt(MenuInfo::getSortOrder));
         }
     }
 
-    private static void separateItemsWithExplicitOrder(Collection<List<MenuInfo>> menus) {
+    private static void separateItemsWithExplicitOrder(Collection<? extends List<MenuInfo>> menus) {
         for (List<MenuInfo> menu : menus) {
             Optional<MenuInfo> firstDefaultSortItem = menu.stream()
                     .filter(info -> info.getSortOrder() == MenuInfo.SORT_ORDER_DEFAULT)
@@ -468,7 +468,7 @@ public static JMenu makeMenu(String category, String actionCommand) {
      * @return the menu
      */
     private static JMenu makeMenu(
-            Collection<MenuInfo> menuInfo, String actionCommand, String menuName) {
+            Collection<? extends MenuInfo> menuInfo, String actionCommand, String menuName) {
 
         JMenu menu = new JMenu(menuName);
         menuInfo.stream()