[#604] Upgrade Checkstyle to version 8.1 (#614)

build.gradle

@@ -42,7 +42,7 @@ allprojects {
         junitVersion = '4.12'
         testFxVersion = '4.0.5-alpha'
         monocleVersion = '1.8.0_20'
-        checkstyleVersion = '7.2'
+        checkstyleVersion = '8.1'
 
         libDir = 'lib'
     }

config/checkstyle/checkstyle.xml

@@ -25,20 +25,19 @@
     <property name="message" value='TODO is preferred to FIXME."' />
   </module>
 
-
-  <!-- Required to allow exceptions in code style -->
-  <module name="SuppressionCommentFilter">
-    <property name="offCommentFormat" value="CHECKSTYLE.OFF\: ([\w\|]+)"/>
-    <property name="onCommentFormat" value="CHECKSTYLE.ON\: ([\w\|]+)"/>
-    <property name="checkFormat" value="$1"/>
-  </module>
-
   <!-- All Java AST specific tests live under TreeWalker module. -->
   <module name="TreeWalker">
 
     <!-- Required for SuppressionCommentFilter to work -->
     <module name="FileContentsHolder"/>
 
+    <!-- Required to allow exceptions in code style -->
+    <module name="SuppressionCommentFilter">
+      <property name="offCommentFormat" value="CHECKSTYLE.OFF\: ([\w\|]+)"/>
+      <property name="onCommentFormat" value="CHECKSTYLE.ON\: ([\w\|]+)"/>
+      <property name="checkFormat" value="$1"/>
+    </module>
+
     <!--
     IMPORT CHECKS
     -->

src/main/java/seedu/address/logic/commands/HelpCommand.java

@@ -1,6 +1,5 @@
 package seedu.address.logic.commands;
 
-
 import seedu.address.commons.core.EventsCenter;
 import seedu.address.commons.events.ui.ShowHelpRequestEvent;
 

src/main/java/seedu/address/model/ReadOnlyAddressBook.java

@@ -1,6 +1,5 @@
 package seedu.address.model;
 
-
 import javafx.collections.ObservableList;
 import seedu.address.model.person.ReadOnlyPerson;
 import seedu.address.model.tag.Tag;

src/main/java/seedu/address/model/person/Address.java

@@ -1,6 +1,5 @@
 package seedu.address.model.person;
 
-
 import static java.util.Objects.requireNonNull;
 
 import seedu.address.commons.exceptions.IllegalValueException;

src/test/java/guitests/guihandles/PersonListPanelHandle.java

@@ -1,6 +1,5 @@
 package guitests.guihandles;
 
-
 import java.util.List;
 import java.util.Optional;
 

src/test/java/seedu/address/commons/util/FileUtilTest.java

@@ -1,6 +1,5 @@
 package seedu.address.commons.util;
 
-
 import static org.junit.Assert.assertEquals;
 
 import java.io.File;

src/test/java/seedu/address/storage/JsonUserPrefsStorageTest.java

@@ -1,6 +1,5 @@
 package seedu.address.storage;
 
-
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 

src/test/java/seedu/address/storage/StorageManagerTest.java

@@ -1,6 +1,5 @@
 package seedu.address.storage;
 
-
 import static junit.framework.TestCase.assertNotNull;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;

src/test/java/seedu/address/storage/XmlAddressBookStorageTest.java

@@ -1,6 +1,5 @@
 package seedu.address.storage;
 
-
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static seedu.address.testutil.TypicalPersons.ALICE;