Java-Edge
diff --git a/‎api/src/main/java/io/grpc/LoadBalancer.java‎
Lines changed: 4 additions & 1 deletion b/‎api/src/main/java/io/grpc/LoadBalancer.java‎
Lines changed: 4 additions & 1 deletion
diff --git a/‎core/src/main/java/io/grpc/internal/GrpcUtil.java‎
Lines changed: 15 additions & 0 deletions b/‎core/src/main/java/io/grpc/internal/GrpcUtil.java‎
Lines changed: 15 additions & 0 deletions
@@ -955,6 +955,8 @@ public abstract static class Helper {
      *
      * <p>It must be called from {@link #getSynchronizationContext the Synchronization Context}
      *
+     * @return Must return a valid Subchannel object, may not return null.
+     *
      * @since 1.22.0
      */
     public Subchannel createSubchannel(CreateSubchannelArgs args) {
@@ -1287,7 +1289,8 @@ public void start(SubchannelStateListener listener) {
      */
     public final EquivalentAddressGroup getAddresses() {
       List<EquivalentAddressGroup> groups = getAllAddresses();
-      Preconditions.checkState(groups.size() == 1, "%s does not have exactly one group", groups);
+      Preconditions.checkState(groups != null && groups.size() == 1,
+          "%s does not have exactly one group", groups);
       return groups.get(0);
     }
 
 
@@ -24,6 +24,7 @@
 import com.google.common.base.Preconditions;
 import com.google.common.base.Splitter;
 import com.google.common.base.Stopwatch;
+import com.google.common.base.Strings;
 import com.google.common.base.Supplier;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
@@ -948,5 +949,19 @@ public static String encodeAuthority(String authority) {
     }
   }
 
+  public static boolean getFlag(String envVarName, boolean enableByDefault) {
+    String envVar = System.getenv(envVarName);
+    if (envVar == null) {
+      envVar = System.getProperty(envVarName);
+    }
+    if (enableByDefault) {
+      return Strings.isNullOrEmpty(envVar) || Boolean.parseBoolean(envVar);
+    } else {
+      return !Strings.isNullOrEmpty(envVar) && Boolean.parseBoolean(envVar);
+    }
+  }
+
+
+
   private GrpcUtil() {}
 }
Original file line number	Diff line number	Diff line change
`@@ -955,6 +955,8 @@ public abstract static class Helper {`
`955`	`955`	`*`
`956`	`956`	`* <p>It must be called from {@link #getSynchronizationContext the Synchronization Context}`
`957`	`957`	`*`
	`958`	`+ * @return Must return a valid Subchannel object, may not return null.`
	`959`	`+ *`
`958`	`960`	`* @since 1.22.0`
`959`	`961`	`*/`
`960`	`962`	`public Subchannel createSubchannel(CreateSubchannelArgs args) {`
`@@ -1287,7 +1289,8 @@ public void start(SubchannelStateListener listener) {`
`1287`	`1289`	`*/`
`1288`	`1290`	`public final EquivalentAddressGroup getAddresses() {`
`1289`	`1291`	`List<EquivalentAddressGroup> groups = getAllAddresses();`
`1290`		`- Preconditions.checkState(groups.size() == 1, "%s does not have exactly one group", groups);`
	`1292`	`+ Preconditions.checkState(groups != null && groups.size() == 1,`
	`1293`	`+ "%s does not have exactly one group", groups);`
`1291`	`1294`	`return groups.get(0);`
`1292`	`1295`	`}`
`1293`	`1296`