--- old/src/java.base/share/classes/java/time/zone/ZoneOffsetTransition.java	2015-04-27 18:10:17.598065730 +0200
+++ new/src/java.base/share/classes/java/time/zone/ZoneOffsetTransition.java	2015-04-27 18:10:17.489067641 +0200
@@ -104,6 +104,10 @@
      */
     private static final long serialVersionUID = -6946044323557704546L;
     /**
+     * The transition epoch-second.
+     */
+    private final long epochSecond;
+    /**
      * The local transition date-time at the transition.
      */
     private final LocalDateTime transition;
@@ -152,6 +156,7 @@
      * @param offsetAfter  the offset at and after the transition, not null
      */
     ZoneOffsetTransition(LocalDateTime transition, ZoneOffset offsetBefore, ZoneOffset offsetAfter) {
+        this.epochSecond = transition.toEpochSecond(offsetBefore);
         this.transition = transition;
         this.offsetBefore = offsetBefore;
         this.offsetAfter = offsetAfter;
@@ -165,6 +170,7 @@
      * @param offsetAfter  the offset at and after the transition, not null
      */
     ZoneOffsetTransition(long epochSecond, ZoneOffset offsetBefore, ZoneOffset offsetAfter) {
+        this.epochSecond = epochSecond;
         this.transition = LocalDateTime.ofEpochSecond(epochSecond, 0, offsetBefore);
         this.offsetBefore = offsetBefore;
         this.offsetAfter = offsetAfter;
@@ -209,7 +215,7 @@
      * @throws IOException if an error occurs
      */
     void writeExternal(DataOutput out) throws IOException {
-        Ser.writeEpochSec(toEpochSecond(), out);
+        Ser.writeEpochSec(epochSecond, out);
         Ser.writeOffset(offsetBefore, out);
         Ser.writeOffset(offsetAfter, out);
     }
@@ -253,7 +259,7 @@
      * @return the transition epoch second
      */
     public long toEpochSecond() {
-        return transition.toEpochSecond(offsetBefore);
+        return epochSecond;
     }
 
     //-------------------------------------------------------------------------