--- old/src/java.desktop/share/classes/javax/swing/DefaultListSelectionModel.java	2017-10-20 16:03:56.217712999 +0530
+++ new/src/java.desktop/share/classes/javax/swing/DefaultListSelectionModel.java	2017-10-20 16:03:56.049796999 +0530
@@ -95,6 +95,7 @@
      * @throws IllegalArgumentException {@inheritDoc}
      */
     public void setSelectionMode(int selectionMode) {
+        int oldMode = this.selectionMode;
         switch (selectionMode) {
         case SINGLE_SELECTION:
         case SINGLE_INTERVAL_SELECTION:
@@ -104,6 +105,23 @@
         default:
             throw new IllegalArgumentException("invalid selectionMode");
         }
+
+        /*
+        This code will only be executed when selection needs to be updated on changing selection mode.
+        It will happen only if selection mode is changed from MULTIPLE_INTERVAL to SINGLE_INTERVAL or SINGLE
+        or from SINGLE_INTERVAL to SINGLE
+         */
+        if (oldMode > this.selectionMode) {
+            if (this.selectionMode == SINGLE_SELECTION) {
+                setSelectionInterval(minIndex, minIndex);
+            } else if (this.selectionMode == SINGLE_INTERVAL_SELECTION) {
+                int selectionEndindex = minIndex;
+                while (value.get(selectionEndindex+1)) {
+                    selectionEndindex++;
+                }
+                setSelectionInterval(minIndex, selectionEndindex);
+            }
+        }
     }
 
     /** {@inheritDoc} */