diff --git a/src/share/classes/java/time/ZoneId.java b/src/share/classes/java/time/ZoneId.java
index 42f390937fbf5c4ec2247ffddfcf7622eae4c521..aabc7fce93bd43123d1529278abd74d4f9fdb587 100644
--- a/src/share/classes/java/time/ZoneId.java
+++ b/src/share/classes/java/time/ZoneId.java
@@ -168,51 +168,6 @@ import java.util.TimeZone;
  */
 public abstract class ZoneId implements Serializable {
 
-    /**
-     * A map of zone overrides to enable the older short time-zone names to be used.
-     * <p>
-     * Use of short zone IDs has been deprecated in {@code java.util.TimeZone}.
-     * This map allows the IDs to continue to be used via the
-     * {@link #of(String, Map)} factory method.
-     * <p>
-     * This map contains an older mapping of the IDs, where 'EST', 'MST' and 'HST'
-     * map to IDs which include daylight savings.
-     * This is in line with versions of TZDB before 2005r.
-     * <p>
-     * This maps as follows:
-     * <ul>
-     * <li>EST - America/New_York</li>
-     * <li>MST - America/Denver</li>
-     * <li>HST - Pacific/Honolulu</li>
-     * <li>ACT - Australia/Darwin</li>
-     * <li>AET - Australia/Sydney</li>
-     * <li>AGT - America/Argentina/Buenos_Aires</li>
-     * <li>ART - Africa/Cairo</li>
-     * <li>AST - America/Anchorage</li>
-     * <li>BET - America/Sao_Paulo</li>
-     * <li>BST - Asia/Dhaka</li>
-     * <li>CAT - Africa/Harare</li>
-     * <li>CNT - America/St_Johns</li>
-     * <li>CST - America/Chicago</li>
-     * <li>CTT - Asia/Shanghai</li>
-     * <li>EAT - Africa/Addis_Ababa</li>
-     * <li>ECT - Europe/Paris</li>
-     * <li>IET - America/Indiana/Indianapolis</li>
-     * <li>IST - Asia/Kolkata</li>
-     * <li>JST - Asia/Tokyo</li>
-     * <li>MIT - Pacific/Apia</li>
-     * <li>NET - Asia/Yerevan</li>
-     * <li>NST - Pacific/Auckland</li>
-     * <li>PLT - Asia/Karachi</li>
-     * <li>PNT - America/Phoenix</li>
-     * <li>PRT - America/Puerto_Rico</li>
-     * <li>PST - America/Los_Angeles</li>
-     * <li>SST - Pacific/Guadalcanal</li>
-     * <li>VST - Asia/Ho_Chi_Minh</li>
-     * </ul>
-     * The map is unmodifiable.
-     */
-    public static final Map<String, String> OLD_SHORT_IDS;
     /**
      * A map of zone overrides to enable the short time-zone names to be used.
      * <p>
@@ -220,9 +175,9 @@ public abstract class ZoneId implements Serializable {
      * This map allows the IDs to continue to be used via the
      * {@link #of(String, Map)} factory method.
      * <p>
-     * This map contains a newer mapping of the IDs, where 'EST', 'MST' and 'HST'
-     * map to IDs which do not include daylight savings
-     * This is in line with TZDB 2005r and later.
+     * This map contains a mapping of the IDs that is in line with TZDB 2005r and
+     * later, where 'EST', 'MST' and 'HST' map to IDs which do not include daylight
+     * savings.
      * <p>
      * This maps as follows:
      * <ul>
@@ -259,42 +214,36 @@ public abstract class ZoneId implements Serializable {
      */
     public static final Map<String, String> SHORT_IDS;
     static {
-        Map<String, String> base = new HashMap<>();
-        base.put("ACT", "Australia/Darwin");
-        base.put("AET", "Australia/Sydney");
-        base.put("AGT", "America/Argentina/Buenos_Aires");
-        base.put("ART", "Africa/Cairo");
-        base.put("AST", "America/Anchorage");
-        base.put("BET", "America/Sao_Paulo");
-        base.put("BST", "Asia/Dhaka");
-        base.put("CAT", "Africa/Harare");
-        base.put("CNT", "America/St_Johns");
-        base.put("CST", "America/Chicago");
-        base.put("CTT", "Asia/Shanghai");
-        base.put("EAT", "Africa/Addis_Ababa");
-        base.put("ECT", "Europe/Paris");
-        base.put("IET", "America/Indiana/Indianapolis");
-        base.put("IST", "Asia/Kolkata");
-        base.put("JST", "Asia/Tokyo");
-        base.put("MIT", "Pacific/Apia");
-        base.put("NET", "Asia/Yerevan");
-        base.put("NST", "Pacific/Auckland");
-        base.put("PLT", "Asia/Karachi");
-        base.put("PNT", "America/Phoenix");
-        base.put("PRT", "America/Puerto_Rico");
-        base.put("PST", "America/Los_Angeles");
-        base.put("SST", "Pacific/Guadalcanal");
-        base.put("VST", "Asia/Ho_Chi_Minh");
-        Map<String, String> pre = new HashMap<>(base);
-        pre.put("EST", "America/New_York");
-        pre.put("MST", "America/Denver");
-        pre.put("HST", "Pacific/Honolulu");
-        OLD_SHORT_IDS = Collections.unmodifiableMap(pre);
-        Map<String, String> post = new HashMap<>(base);
-        post.put("EST", "-05:00");
-        post.put("MST", "-07:00");
-        post.put("HST", "-10:00");
-        SHORT_IDS = Collections.unmodifiableMap(post);
+        Map<String, String> map = new HashMap<>(64);
+        map.put("ACT", "Australia/Darwin");
+        map.put("AET", "Australia/Sydney");
+        map.put("AGT", "America/Argentina/Buenos_Aires");
+        map.put("ART", "Africa/Cairo");
+        map.put("AST", "America/Anchorage");
+        map.put("BET", "America/Sao_Paulo");
+        map.put("BST", "Asia/Dhaka");
+        map.put("CAT", "Africa/Harare");
+        map.put("CNT", "America/St_Johns");
+        map.put("CST", "America/Chicago");
+        map.put("CTT", "Asia/Shanghai");
+        map.put("EAT", "Africa/Addis_Ababa");
+        map.put("ECT", "Europe/Paris");
+        map.put("IET", "America/Indiana/Indianapolis");
+        map.put("IST", "Asia/Kolkata");
+        map.put("JST", "Asia/Tokyo");
+        map.put("MIT", "Pacific/Apia");
+        map.put("NET", "Asia/Yerevan");
+        map.put("NST", "Pacific/Auckland");
+        map.put("PLT", "Asia/Karachi");
+        map.put("PNT", "America/Phoenix");
+        map.put("PRT", "America/Puerto_Rico");
+        map.put("PST", "America/Los_Angeles");
+        map.put("SST", "Pacific/Guadalcanal");
+        map.put("VST", "Asia/Ho_Chi_Minh");
+        map.put("EST", "-05:00");
+        map.put("MST", "-07:00");
+        map.put("HST", "-10:00");
+        SHORT_IDS = Collections.unmodifiableMap(map);
     }
     /**
      * Serialization version.
@@ -314,7 +263,7 @@ public abstract class ZoneId implements Serializable {
      * @throws ZoneRulesException if the converted zone region ID cannot be found
      */
     public static ZoneId systemDefault() {
-        return ZoneId.of(TimeZone.getDefault().getID(), SHORT_IDS);
+        return TimeZone.getDefault().toZoneId();
     }
 
     /**
diff --git a/src/share/classes/java/time/zone/TzdbZoneRulesProvider.java b/src/share/classes/java/time/zone/TzdbZoneRulesProvider.java
index b40fe987babdab02448e9a0d8130133832d05d80..6a9d0127b0730b51c642d904fdfbc8bc8c67b037 100644
--- a/src/share/classes/java/time/zone/TzdbZoneRulesProvider.java
+++ b/src/share/classes/java/time/zone/TzdbZoneRulesProvider.java
@@ -62,6 +62,7 @@
 package java.time.zone;
 
 import java.io.ByteArrayInputStream;
+import java.io.BufferedInputStream;
 import java.io.DataInputStream;
 import java.io.File;
 import java.io.FileInputStream;
@@ -107,7 +108,8 @@ final class TzdbZoneRulesProvider extends ZoneRulesProvider {
         try {
             String libDir = System.getProperty("java.home") + File.separator + "lib";
             try (DataInputStream dis = new DataInputStream(
-                     new FileInputStream(new File(libDir, "tzdb.dat")))) {
+                     new BufferedInputStream(new FileInputStream(
+                         new File(libDir, "tzdb.dat"))))) {
                 load(dis);
             }
         } catch (Exception ex) {
diff --git a/src/share/classes/java/util/TimeZone.java b/src/share/classes/java/util/TimeZone.java
index aebe6859e9460a9c5bb3e07bfe4f40077c17a106..c798b656345f62fa29141e1a0c3cab44eabe088f 100644
--- a/src/share/classes/java/util/TimeZone.java
+++ b/src/share/classes/java/util/TimeZone.java
@@ -544,7 +544,16 @@ abstract public class TimeZone implements Serializable, Cloneable {
      * @since 1.8
      */
     public ZoneId toZoneId() {
-        return ZoneId.of(getID(), ZoneId.SHORT_IDS);
+        String id = getID();
+        if (ZoneInfoFile.useOldMapping() && id.length() == 3) {
+            if ("EST".equals(id))
+                return ZoneId.of("America/New_York");
+            if ("MST".equals(id))
+                return ZoneId.of("America/Denver");
+            if ("HST".equals(id))
+                return ZoneId.of("America/Honolulu");
+        }
+        return ZoneId.of(id, ZoneId.SHORT_IDS);
     }
 
     private static TimeZone getTimeZone(String ID, boolean fallback) {
diff --git a/src/share/classes/sun/util/calendar/ZoneInfoFile.java b/src/share/classes/sun/util/calendar/ZoneInfoFile.java
index 60cd91911a27372a79e3d38c3709d01050965f06..2434bbcbd3936613cbf22893335c6523b0610a84 100644
--- a/src/share/classes/sun/util/calendar/ZoneInfoFile.java
+++ b/src/share/classes/sun/util/calendar/ZoneInfoFile.java
@@ -26,6 +26,7 @@
 package sun.util.calendar;
 
 import java.io.ByteArrayInputStream;
+import java.io.BufferedInputStream;
 import java.io.DataInput;
 import java.io.DataInputStream;
 import java.io.File;
@@ -243,7 +244,8 @@ public final class ZoneInfoFile {
                 try {
                     String libDir = System.getProperty("java.home") + File.separator + "lib";
                     try (DataInputStream dis = new DataInputStream(
-                             new FileInputStream(new File(libDir, "tzdb.dat")))) {
+                             new BufferedInputStream(new FileInputStream(
+                                 new File(libDir, "tzdb.dat"))))) {
                         load(dis);
                     }
                 } catch (Exception x) {
@@ -265,6 +267,10 @@ public final class ZoneInfoFile {
         }
     }
 
+    public static boolean useOldMapping() {
+       return USE_OLDMAPPING;
+    }
+
     /**
      * Loads the rules from a DateInputStream
      *
diff --git a/test/java/time/tck/java/time/TCKZoneId.java b/test/java/time/tck/java/time/TCKZoneId.java
index c036deeb7e7cf5df8d6a673c5b76a6047a8f0703..a90c9abf48e37ad351ad8420efcc5c30255c00a9 100644
--- a/test/java/time/tck/java/time/TCKZoneId.java
+++ b/test/java/time/tck/java/time/TCKZoneId.java
@@ -93,47 +93,6 @@ import org.testng.annotations.Test;
 @Test
 public class TCKZoneId extends AbstractTCKTest {
 
-    //-----------------------------------------------------------------------
-    // OLD_SHORT_IDS
-    //-----------------------------------------------------------------------
-    public void test_constant_OLD_IDS_PRE_2005() {
-        Map<String, String> ids = ZoneId.OLD_SHORT_IDS;
-        assertEquals(ids.get("EST"), "America/New_York");
-        assertEquals(ids.get("MST"), "America/Denver");
-        assertEquals(ids.get("HST"), "Pacific/Honolulu");
-        assertEquals(ids.get("ACT"), "Australia/Darwin");
-        assertEquals(ids.get("AET"), "Australia/Sydney");
-        assertEquals(ids.get("AGT"), "America/Argentina/Buenos_Aires");
-        assertEquals(ids.get("ART"), "Africa/Cairo");
-        assertEquals(ids.get("AST"), "America/Anchorage");
-        assertEquals(ids.get("BET"), "America/Sao_Paulo");
-        assertEquals(ids.get("BST"), "Asia/Dhaka");
-        assertEquals(ids.get("CAT"), "Africa/Harare");
-        assertEquals(ids.get("CNT"), "America/St_Johns");
-        assertEquals(ids.get("CST"), "America/Chicago");
-        assertEquals(ids.get("CTT"), "Asia/Shanghai");
-        assertEquals(ids.get("EAT"), "Africa/Addis_Ababa");
-        assertEquals(ids.get("ECT"), "Europe/Paris");
-        assertEquals(ids.get("IET"), "America/Indiana/Indianapolis");
-        assertEquals(ids.get("IST"), "Asia/Kolkata");
-        assertEquals(ids.get("JST"), "Asia/Tokyo");
-        assertEquals(ids.get("MIT"), "Pacific/Apia");
-        assertEquals(ids.get("NET"), "Asia/Yerevan");
-        assertEquals(ids.get("NST"), "Pacific/Auckland");
-        assertEquals(ids.get("PLT"), "Asia/Karachi");
-        assertEquals(ids.get("PNT"), "America/Phoenix");
-        assertEquals(ids.get("PRT"), "America/Puerto_Rico");
-        assertEquals(ids.get("PST"), "America/Los_Angeles");
-        assertEquals(ids.get("SST"), "Pacific/Guadalcanal");
-        assertEquals(ids.get("VST"), "Asia/Ho_Chi_Minh");
-    }
-
-    @Test(expectedExceptions=UnsupportedOperationException.class)
-    public void test_constant_OLD_IDS_PRE_2005_immutable() {
-        Map<String, String> ids = ZoneId.OLD_SHORT_IDS;
-        ids.clear();
-    }
-
     //-----------------------------------------------------------------------
     // SHORT_IDS
     //-----------------------------------------------------------------------
diff --git a/test/java/util/Calendar/JavatimeTest.java b/test/java/util/Calendar/JavatimeTest.java
index 9f61229e1dc459f3be8ad91920a9b67915dd34df..6a0a4ff9a66a9d54f4bcf160918376206a26a7d6 100644
--- a/test/java/util/Calendar/JavatimeTest.java
+++ b/test/java/util/Calendar/JavatimeTest.java
@@ -114,14 +114,14 @@ public class JavatimeTest {
                 zidStr.equals("MST")) {
                 continue;
             }
-            ZoneId zid = ZoneId.of(zidStr, ZoneId.OLD_SHORT_IDS);
+            ZoneId zid = ZoneId.of(zidStr, ZoneId.SHORT_IDS);
             if (!zid.equals(TimeZone.getTimeZone(zid).toZoneId())) {
                 throw new RuntimeException("FAILED: zid -> tz -> zid :" + zidStr);
             }
             TimeZone tz = TimeZone.getTimeZone(zidStr);
             // no round-trip for alias and "GMT"
             if (!tz.equals(TimeZone.getTimeZone(tz.toZoneId())) &&
-                !ZoneId.OLD_SHORT_IDS.containsKey(zidStr) &&
+                !ZoneId.SHORT_IDS.containsKey(zidStr) &&
                 !zidStr.startsWith("GMT")) {
                 throw new RuntimeException("FAILED: tz -> zid -> tz :" + zidStr);
             }