--- jsr166/src/jsr166e/CompletableFuture.java	2013/01/02 14:13:12	1.1
+++ jsr166/src/jsr166e/CompletableFuture.java	2013/01/02 17:37:14	1.2
@@ -403,7 +403,7 @@ public class CompletableFuture<T> implem
         }
         public final boolean exec() {
             CompletableFuture<Void> d; Throwable ex;
-            if ((d = this.dst) != null) {
+            if ((d = this.dst) != null && d.result == null) {
                 try {
                     fn.run();
                     ex = null;
@@ -425,7 +425,7 @@ public class CompletableFuture<T> implem
         }
         public final boolean exec() {
             CompletableFuture<U> d; U u; Throwable ex;
-            if ((d = this.dst) != null) {
+            if ((d = this.dst) != null && d.result == null) {
                 try {
                     u = fn.get();
                     ex = null;
@@ -450,7 +450,7 @@ public class CompletableFuture<T> implem
         }
         public final boolean exec() {
             CompletableFuture<U> d; U u; Throwable ex;
-            if ((d = this.dst) != null) {
+            if ((d = this.dst) != null && d.result == null) {
                 try {
                     u = fn.apply(arg);
                     ex = null;
@@ -477,7 +477,7 @@ public class CompletableFuture<T> implem
         }
         public final boolean exec() {
             CompletableFuture<V> d; V v; Throwable ex;
-            if ((d = this.dst) != null) {
+            if ((d = this.dst) != null && d.result == null) {
                 try {
                     v = fn.apply(arg1, arg2);
                     ex = null;
@@ -502,7 +502,7 @@ public class CompletableFuture<T> implem
         }
         public final boolean exec() {
             CompletableFuture<Void> d; Throwable ex;
-            if ((d = this.dst) != null) {
+            if ((d = this.dst) != null && d.result == null) {
                 try {
                     fn.accept(arg);
                     ex = null;
@@ -528,7 +528,7 @@ public class CompletableFuture<T> implem
         }
         public final boolean exec() {
             CompletableFuture<Void> d; Throwable ex;
-            if ((d = this.dst) != null) {
+            if ((d = this.dst) != null && d.result == null) {
                 try {
                     fn.accept(arg1, arg2);
                     ex = null;