Require at least JDK 8 and Maven 3.3.9 for build

.travis.sh

@@ -47,10 +47,7 @@ case "$JDK" in
 5)
   install_jdk $JDK5_URL false
   ;;
-6)
-  ;;
-7)
-  jdk_switcher /usr/lib/jvm/java-7-openjdk-amd64
+6 | 7)
   ;;
 8)
   jdk_switcher /usr/lib/jvm/java-8-oracle
@@ -91,7 +88,7 @@ case "$JDK" in
   mvn -V -B -e verify -Djdk.version=1.6 -Dbytecode.version=1.6 --toolchains=./.travis/travis-toolchains.xml
   ;;
 7)
-  mvn -V -B -e verify -Dbytecode.version=1.7
+  mvn -V -B -e verify -Djdk.version=1.7 -Dbytecode.version=1.7 --toolchains=./.travis/travis-toolchains.xml
   ;;
 8 | 8-ea)
   mvn -V -B -e verify -Dbytecode.version=1.8 -Decj=${ECJ:-}

.travis/travis-toolchains.xml

@@ -10,4 +10,13 @@
       <jdkHome>/usr/lib/jvm/java-6-openjdk-amd64</jdkHome>
     </configuration>
   </toolchain>
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>1.7</version>
+    </provides>
+    <configuration>
+      <jdkHome>/usr/lib/jvm/java-7-openjdk-amd64</jdkHome>
+    </configuration>
+  </toolchain>
 </toolchains>

org.jacoco.build/pom.xml

@@ -83,10 +83,6 @@
     </contributor>
   </contributors>
 
-  <prerequisites>
-    <maven>3.0</maven>
-  </prerequisites>
-
   <modules>
     <!-- Order is important: org.jacoco.agent.rt embeds into org.jacoco.agent and JaCoCo Agent used during tests -->
     <module>../org.jacoco.core</module>
@@ -323,7 +319,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-enforcer-plugin</artifactId>
-          <version>1.0.1</version>
+          <version>3.0.0-M2</version>
         </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
@@ -524,6 +520,12 @@
             </goals>
             <configuration>
               <rules>
+                <requireJavaVersion>
+                  <version>1.8</version>
+                </requireJavaVersion>
+                <requireMavenVersion>
+                  <version>3.3.9</version>
+                </requireMavenVersion>
                 <requireNoRepositories>
                   <message>The rules for repo1.maven.org are that pom.xml files should not include repository definitions.</message>
                   <banRepositories>true</banRepositories>
@@ -533,10 +535,6 @@
                   <message>No SNAPSHOT versions allowed for dependencies</message>
                   <onlyWhenRelease>true</onlyWhenRelease>
                 </requireReleaseDeps>
-                <requireMavenVersion>
-                  <!-- Maven 3.0.3 contains bug - see http://jira.codehaus.org/browse/MINVOKER-107 -->
-                  <version>[3.0.0,3.0.3),[3.0.4,)</version>
-                </requireMavenVersion>
               </rules>
             </configuration>
           </execution>

org.jacoco.doc/docroot/doc/build.html

@@ -23,10 +23,10 @@ <h1>Build</h1>
 <p>
   The JaCoCo build is based on <a href="http://maven.apache.org/">Maven</a> and
   can be locally executed on every machine with a proper
-  <a href="environment.html">environment setup</a>. In particular you need a
-  <a href="http://maven.apache.org/">Maven 3</a> installation.  Developers are
-  encouraged to run the build before every commit to ensure consistency of the
-  source tree.
+  <a href="environment.html">environment setup</a>. In particular you need at
+  least <a href="http://maven.apache.org/">Maven 3.3.9</a> installation.
+  Developers are encouraged to run the build before every commit to ensure
+  consistency of the source tree.
 </p>
 
 

org.jacoco.doc/docroot/doc/environment.html

@@ -74,7 +74,8 @@ <h3>JRE/JDK</h3>
 <h3>Build</h3>
 
 <p>
-  The JaCoCo build is based on <a href="http://maven.apache.org/">Maven 3</a>.
+  The JaCoCo build is based on <a href="http://maven.apache.org/">Maven</a>
+  and requires at least Maven 3.3.9.
   See the <a href="build.html">build description</a> for details.
 </p>