Use maven-enforcer-plugin to ensure none of the dependencies are compiled for Java 8+

h2/pom.xml

@@ -243,6 +243,35 @@
           </signature>
         </configuration>
       </plugin>
+      <!-- Make sure none of our dependencies use anything outside JDK 1.7 -->
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-enforcer-plugin</artifactId>
+        <version>3.0.0-M1</version>
+        <executions>
+          <execution>
+            <id>enforce-bytecode-version</id>
+            <goals>
+              <goal>enforce</goal>
+            </goals>
+            <configuration>
+              <rules>
+                <enforceBytecodeVersion>
+                  <maxJdkVersion>1.7</maxJdkVersion>
+                </enforceBytecodeVersion>
+              </rules>
+              <fail>true</fail>
+            </configuration>
+          </execution>
+        </executions>
+        <dependencies>
+          <dependency>
+            <groupId>org.codehaus.mojo</groupId>
+            <artifactId>extra-enforcer-rules</artifactId>
+            <version>1.0-beta-6</version>
+          </dependency>
+        </dependencies>
+      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>