update to JDK 11

Author: Daniel Muehlbachler

.travis.yml

@@ -22,11 +22,11 @@ branches:
 matrix:
   fast_finish: true
   include:
-    - jdk: openjdk8
+    - jdk: openjdk11
       env: CMD="./.ci/travis.sh install"
 
-    - jdk: openjdk8
+    - jdk: openjdk11
       env: CMD="./.ci/travis.sh integration-tests"
 
-    - jdk: openjdk8
+    - jdk: openjdk11
       env: CMD="./.ci/travis.sh nondex"

pom.xml

@@ -105,7 +105,7 @@
       8.28
     </maven.sevntu.checkstyle.plugin.checkstyle.version>
     <maven.jacoco.plugin.version>0.8.5</maven.jacoco.plugin.version>
-    <java.version>1.8</java.version>
+    <java.version>11</java.version>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <!-- we disable ITs by default as it need download of 200MB sonar application jar -->
     <skipITs>true</skipITs>
@@ -718,7 +718,7 @@
             <configuration>
               <rules>
                 <requireJavaVersion>
-                  <version>1.8</version>
+                  <version>${java.version}</version>
                 </requireJavaVersion>
                 <requireMavenVersion>
                   <version>3.0.1</version>

src/main/java/org/sonar/plugins/checkstyle/CheckstyleProfileExporter.java

@@ -28,6 +28,8 @@
 import java.util.List;
 import java.util.Map;
 
+import javax.annotation.Nullable;
+
 import org.apache.commons.lang.StringEscapeUtils;
 import org.apache.commons.lang.StringUtils;
 import org.sonar.api.ExtensionPoint;
@@ -224,7 +226,7 @@ private static void appendRuleParameters(Writer writer, ActiveRuleWrapper active
     }
 
     private static void appendModuleProperty(Writer writer, String propertyKey,
-            String propertyValue) throws IOException {
+            @Nullable String propertyValue) throws IOException {
         if (StringUtils.isNotBlank(propertyValue)) {
             writer.append("<property name=\"");
             StringEscapeUtils.escapeXml(writer, propertyKey);

src/test/java/org/sonar/plugins/checkstyle/internal/ChecksTest.java

@@ -19,8 +19,6 @@
 
 package org.sonar.plugins.checkstyle.internal;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
-
 import java.beans.PropertyDescriptor;
 import java.io.File;
 import java.io.FileInputStream;
@@ -94,16 +92,18 @@ public void verifyTestConfigurationFiles() throws Exception {
     }
 
     private static void validateSonarRules(Set<Class<?>> modules)
-            throws ParserConfigurationException, IOException {
+            throws ParserConfigurationException {
         final File rulesFile = new File(RULES_PATH);
 
         Assert.assertTrue(RULES_PATH + " must exist", rulesFile.exists());
 
-        final String input = new String(Files.readAllBytes(rulesFile.toPath()), UTF_8);
-
-        final Document document = XmlUtil.getRawXml(rulesFile.getAbsolutePath(), input, input);
-
-        validateSonarRules(document, modules);
+        try {
+            final String input = Files.readString(rulesFile.toPath());
+            final Document document = XmlUtil.getRawXml(rulesFile.getAbsolutePath(), input, input);
+            validateSonarRules(document, modules);
+        } catch(IOException ignored) {
+            Assert.fail("Failed to read rulesFile.");
+        }
     }
 
     private static void validateSonarRules(Document document, Set<Class<?>> modules) {

wercker.yml

@@ -1,4 +1,4 @@
-box: maven:3.5.2-jdk-8
+box: maven:3.6.3-jdk-11
 
 build:
   steps: