Add Java 11 to the testsuite

.travis.yml

@@ -23,8 +23,18 @@ dist: bionic
 matrix:
   include:
   - language: java
+    name: java11
+    jdk: openjdk11
+    before_cache:
+      - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
+      - rm -fr $HOME/.gradle/caches/*/plugin-resolution/
+    cache:
+      directories:
+        - $HOME/.gradle/caches/
+        - $HOME/.gradle/wrapper/
+  - language: java
+    name: java8
     jdk: openjdk8
-    name: java
     before_cache:
       - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
       - rm -fr $HOME/.gradle/caches/*/plugin-resolution/

build.gradle

@@ -40,10 +40,6 @@ plugins {
   id 'com.palantir.consistent-versions' version '1.9.2'
 }
 
-if (JavaVersion.current() != JavaVersion.VERSION_1_8) {
-  throw new GradleException("This build must be run with Java 8")
-}
-
 allprojects {
   group = "org.apache.iceberg"
   version = getProjectVersion()
@@ -54,6 +50,9 @@ allprojects {
   }
 }
 
+sourceCompatibility = '1.8'
+targetCompatibility = '1.8'
+
 subprojects {
   apply plugin: 'java'
 
@@ -321,7 +320,7 @@ project(':iceberg-spark') {
     compile project(':iceberg-hive')
 
     compileOnly "org.apache.avro:avro"
-    compileOnly("org.apache.spark:spark-hive_2.11") {
+    compileOnly("org.apache.spark:spark-hive_2.12") {
       exclude group: 'org.apache.avro', module: 'avro'
     }
 
@@ -348,7 +347,7 @@ project(':iceberg-spark') {
     // dependency only to the jmh configuration, however gradle-consistent-versions
     // plugin does not respect this configuration and does not seem to have a way
     // to add custom configurations in its lockable configuration detection
-    compileOnly("org.apache.spark:spark-avro_2.11") {
+    compileOnly("org.apache.spark:spark-avro_2.12") {
       exclude group: 'org.apache.avro', module: 'avro'
     }
   }

deploy.gradle

@@ -17,6 +17,10 @@
  * under the License.
  */
 
+if (project.hasProperty('release') && JavaVersion.current() != JavaVersion.VERSION_1_8) {
+  throw new GradleException("Releases must be built with Java 8")
+}
+
 subprojects {
   apply plugin: 'maven' // make pom files for deployment
   apply plugin: 'maven-publish'

hive/src/test/java/org/apache/iceberg/hive/HiveMetastoreTest.java

@@ -49,13 +49,19 @@ public static void startMetastore() throws Exception {
 
   @AfterClass
   public static void stopMetastore() {
-    catalog.close();
-    HiveMetastoreTest.catalog = null;
+    if (catalog != null) {
+      catalog.close();
+      HiveMetastoreTest.catalog = null;
+    }
 
-    metastoreClient.close();
-    HiveMetastoreTest.metastoreClient = null;
+    if (metastoreClient != null) {
+      metastoreClient.close();
+      HiveMetastoreTest.metastoreClient = null;
+    }
 
-    metastore.stop();
-    HiveMetastoreTest.metastore = null;
+    if (metastore != null) {
+      metastore.stop();
+      HiveMetastoreTest.metastore = null;
+    }
   }
 }