address another set of error-prone warnings

jflex/src/main/java/jflex/core/AbstractLexScan.java

@@ -2,10 +2,11 @@
 
 import java.io.File;
 import java.io.FileNotFoundException;
+import java.util.ArrayDeque;
 import java.util.ArrayList;
+import java.util.Deque;
 import java.util.List;
 import java.util.Set;
-import java.util.Stack;
 import java_cup.runtime.Symbol;
 import jflex.core.unicode.CharClasses;
 import jflex.core.unicode.ILexScan;
@@ -22,8 +23,7 @@ public abstract class AbstractLexScan implements ILexScan {
 
   File file;
 
-  @SuppressWarnings("JdkObsolete")
-  private final Stack<File> files = new Stack<>();
+  private final Deque<File> files = new ArrayDeque<>();
 
   StringBuilder userCode = new StringBuilder();
 
@@ -186,7 +186,7 @@ void includeFile(String filePath) {
       throw new ScannerException(file, ErrorMessages.NOT_READABLE, lexLine());
     }
     // check for cycle
-    if (files.search(f) > 0) {
+    if (files.contains(f)) {
       throw new ScannerException(file, ErrorMessages.FILE_CYCLE, lexLine());
     }
     try {

jflex/src/main/java/jflex/gui/GeneratorThread.java

@@ -35,7 +35,7 @@ public class GeneratorThread extends Thread {
   String outputDir;
 
   /** main UI component, likes to be notified when generator finishes */
-  MainFrame parent;
+  final MainFrame parent;
 
   /**
    * Create a new GeneratorThread, but do not run it yet.

jflex/src/main/java/jflex/gui/GridPanel.java

@@ -10,7 +10,8 @@
 package jflex.gui;
 
 import java.awt.*;
-import java.util.Vector;
+import java.util.ArrayList;
+import java.util.List;
 
 /**
  * Grid layout manager like GridLayout but with predefinable grid size.
@@ -28,7 +29,7 @@ public class GridPanel extends Panel implements Handles {
   private final int hgap;
   private final int vgap;
 
-  private final Vector<GridPanelConstraint> constraints = new Vector<>();
+  private final List<GridPanelConstraint> constraints = new ArrayList<>();
   private Insets insets = new Insets(0, 0, 0, 0);
 
   /** {@inheritDoc} */
@@ -62,7 +63,7 @@ public void doLayout() {
     float cellHeight = size.height / rows;
 
     for (int i = 0; i < constraints.size(); i++) {
-      GridPanelConstraint c = constraints.elementAt(i);
+      GridPanelConstraint c = constraints.get(i);
 
       float x = cellWidth * c.x + insets.left + hgap / 2;
       float y = cellHeight * c.y + insets.right + vgap / 2;
@@ -124,7 +125,7 @@ public Dimension getPreferredSize() {
     float dx = 0;
 
     for (int i = 0; i < constraints.size(); i++) {
-      GridPanelConstraint c = constraints.elementAt(i);
+      GridPanelConstraint c = constraints.get(i);
 
       Dimension d = c.component.getPreferredSize();
 
@@ -168,18 +169,9 @@ public void add(int x, int y, int dx, int dy, Component c) {
     add(x, y, dx, dy, FILL, c);
   }
 
-  /**
-   * add.
-   *
-   * @param x a int.
-   * @param y a int.
-   * @param dx a int.
-   * @param dy a int.
-   * @param handle a int.
-   * @param c a {@link java.awt.Component} object.
-   */
+  /** Add a component to this panel. */
   public void add(int x, int y, int dx, int dy, int handle, Component c) {
     super.add(c);
-    constraints.addElement(new GridPanelConstraint(x, y, dx, dy, handle, c));
+    constraints.add(new GridPanelConstraint(x, y, dx, dy, handle, c));
   }
 }

jflex/src/main/java/jflex/gui/GridPanelConstraint.java

@@ -18,8 +18,12 @@
  */
 public class GridPanelConstraint {
 
-  int x, y, width, height, handle;
-  Component component;
+  final int x;
+  final int y;
+  final int width;
+  final int height;
+  final int handle;
+  final Component component;
 
   /**
    * Constructor for GridPanelConstraint.

jflex/src/main/java/jflex/gui/MainFrame.java

@@ -28,7 +28,6 @@
  */
 public final class MainFrame extends Frame implements Handles {
 
-  /** */
   private static final long serialVersionUID = 3296137982410640865L;
 
   private volatile boolean choosing;

jflex/src/main/java/jflex/gui/OptionsDialog.java

@@ -32,7 +32,7 @@ public class OptionsDialog extends Dialog {
 
   private static final long serialVersionUID = 6807759416163314769L;
 
-  private Frame owner;
+  private final Frame owner;
 
   private TextField skelFile;
 

jflex/src/main/jflex/skeleton.nested

@@ -82,8 +82,8 @@
   private int zzFinalHighSurrogate = 0;
 
   /** the stack of open (nested) input streams to read from */
-  private java.util.Stack<ZzFlexStreamInfo> zzStreams
-    = new java.util.Stack<ZzFlexStreamInfo>();
+  private java.util.Deque<ZzFlexStreamInfo> zzStreams
+    = new java.util.ArrayDeque<ZzFlexStreamInfo>();
 
   /**
    * inner class used to store info for nested
@@ -236,7 +236,7 @@
    * Closes the current input stream and continues to
    * read from the one on top of the stream stack. 
    *
-   * @throws java.util.EmptyStackException
+   * @throws java.util.NoSuchElementException
    *         if there is no further stream to read from.
    *
    * @throws java.io.IOException

jflex/src/test/java/jflex/anttask/JFlexTaskTest.java

@@ -112,7 +112,7 @@ public void testNobak() {
   public void testSkel() {
     task.setVerbose(false); // avoid to java console pop up
     task.setSkeleton(new File("src/main/jflex/skeleton.nested"));
-    assertThat(Skeleton.line[3].indexOf("java.util.Stack") > 0).isTrue();
+    assertThat(Skeleton.line[3].indexOf("java.util.Deque") > 0).isTrue();
   }
 
   @Test

jflex/src/test/java/jflex/skeleton/SkeletonTest.java

@@ -56,8 +56,8 @@ public void readSkelFile_bazel() throws FileNotFoundException {
   }
 
   private void checkDefaultSkeleton() {
-    assertThat(Skeleton.line[3]).contains("java.util.Stack");
+    assertThat(Skeleton.line[3]).contains("java.util.Deque");
     Skeleton.readDefault();
-    assertThat(Skeleton.line[3]).doesNotContain("java.util.Stack");
+    assertThat(Skeleton.line[3]).doesNotContain("java.util.Deque");
   }
 }