diff --git a/complete/build.gradle b/complete/build.gradle
index 64ee6045818cb5d2cc1a5261e2d9da979b1f74f4..0a5eeee02ec2145b0f2f08fefb7e49f0114be07c 100644
--- a/complete/build.gradle
+++ b/complete/build.gradle
@@ -21,6 +21,9 @@ repositories {
     mavenCentral()
 }
 
+sourceCompatibility = 1.7
+targetCompatibility = 1.7
+
 dependencies {
     compile("org.springframework.boot:spring-boot-starter-web")
     // tag::actuator[]
diff --git a/initial/build.gradle b/initial/build.gradle
index 85a0b14145f4a4331a01d2faa5fa4c754d060b03..1d01ba02994e919b5ffae03246388e508985b448 100644
--- a/initial/build.gradle
+++ b/initial/build.gradle
@@ -21,6 +21,9 @@ repositories {
     mavenCentral()
 }
 
+sourceCompatibility = 1.7
+targetCompatibility = 1.7
+
 dependencies {
     // tag::jetty[]
     compile("org.springframework.boot:spring-boot-starter-web") {