diff --git a/java/google/registry/env/alpha/backend/WEB-INF/appengine-web.xml b/java/google/registry/env/alpha/backend/WEB-INF/appengine-web.xml
index c0e446e70..278a903a2 100644
--- a/java/google/registry/env/alpha/backend/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/alpha/backend/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>backend</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/alpha/default/WEB-INF/appengine-web.xml b/java/google/registry/env/alpha/default/WEB-INF/appengine-web.xml
index 932dfc3af..4c7953a88 100644
--- a/java/google/registry/env/alpha/default/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/alpha/default/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>default</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/alpha/tools/WEB-INF/appengine-web.xml b/java/google/registry/env/alpha/tools/WEB-INF/appengine-web.xml
index c457c723b..2f534d70f 100644
--- a/java/google/registry/env/alpha/tools/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/alpha/tools/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>tools</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/crash/backend/WEB-INF/appengine-web.xml b/java/google/registry/env/crash/backend/WEB-INF/appengine-web.xml
index 9b9cc5403..b6f8925b3 100644
--- a/java/google/registry/env/crash/backend/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/crash/backend/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>backend</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/crash/default/WEB-INF/appengine-web.xml b/java/google/registry/env/crash/default/WEB-INF/appengine-web.xml
index ac8696486..f5f277ff9 100644
--- a/java/google/registry/env/crash/default/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/crash/default/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>default</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/crash/tools/WEB-INF/appengine-web.xml b/java/google/registry/env/crash/tools/WEB-INF/appengine-web.xml
index 72aac3b85..de738b6cd 100644
--- a/java/google/registry/env/crash/tools/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/crash/tools/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>tools</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/local/backend/WEB-INF/appengine-web.xml b/java/google/registry/env/local/backend/WEB-INF/appengine-web.xml
index afe90f338..a5e451cf2 100644
--- a/java/google/registry/env/local/backend/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/local/backend/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>backend</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/local/default/WEB-INF/appengine-web.xml b/java/google/registry/env/local/default/WEB-INF/appengine-web.xml
index bb32914cd..ab0a2ccac 100644
--- a/java/google/registry/env/local/default/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/local/default/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>default</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/local/tools/WEB-INF/appengine-web.xml b/java/google/registry/env/local/tools/WEB-INF/appengine-web.xml
index 5d1a17d65..620019593 100644
--- a/java/google/registry/env/local/tools/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/local/tools/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>tools</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/sandbox/backend/WEB-INF/appengine-web.xml b/java/google/registry/env/sandbox/backend/WEB-INF/appengine-web.xml
index 1b874a71e..d5d99c459 100644
--- a/java/google/registry/env/sandbox/backend/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/sandbox/backend/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>backend</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/sandbox/default/WEB-INF/appengine-web.xml b/java/google/registry/env/sandbox/default/WEB-INF/appengine-web.xml
index 16257498e..38351d263 100644
--- a/java/google/registry/env/sandbox/default/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/sandbox/default/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>default</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>
diff --git a/java/google/registry/env/sandbox/tools/WEB-INF/appengine-web.xml b/java/google/registry/env/sandbox/tools/WEB-INF/appengine-web.xml
index 4e1800c41..94e5f4a84 100644
--- a/java/google/registry/env/sandbox/tools/WEB-INF/appengine-web.xml
+++ b/java/google/registry/env/sandbox/tools/WEB-INF/appengine-web.xml
@@ -3,6 +3,7 @@
 
   <application>domain-registry</application>
   <version>1</version>
+  <runtime>java8</runtime>
   <module>tools</module>
   <threadsafe>true</threadsafe>
   <sessions-enabled>true</sessions-enabled>