src/share/classes/javax/swing/plaf/synth/SynthSliderUI.java

@@ -390,11 +390,11 @@
                 // Calculate the track rectangle.  It is necessary for
                 // xPositionForValue to return correct values.
                 trackRect.x = insetCache.left;
                 trackRect.width = contentRect.width;
 
-                Dictionary<Integer, JComponent> dictionary = slider.getLabelTable();
+                Dictionary<Integer, ? extends JComponent> dictionary = slider.getLabelTable();
                 if (dictionary != null) {
                     int minValue = slider.getMinimum();
                     int maxValue = slider.getMaximum();
 
                     // Iterate through the keys in the dictionary and find the