Make Java 8 detection work on Java 9

Closes #393.

worldedit-bukkit/src/main/java/com/sk89q/worldedit/bukkit/WorldEditPlugin.java

@@ -48,7 +48,7 @@ import com.sk89q.worldedit.regions.CylinderRegion;
 import com.sk89q.worldedit.regions.Polygonal2DRegion;
 import com.sk89q.worldedit.regions.Region;
 import com.sk89q.worldedit.regions.RegionSelector;
-import com.sk89q.worldedit.util.Java8Detector;
+import com.sk89q.worldedit.util.Java7Detector;
 
 import org.bukkit.World;
 import org.bukkit.command.Command;
@@ -121,7 +121,7 @@ public class WorldEditPlugin extends JavaPlugin implements TabCompleter {
         loadAdapter(); // Need an adapter to work with special blocks with NBT data
 
         // Check Java version
-        Java8Detector.notifyIfNot8();
+        Java7Detector.notifyIfNot8();
     }
 
     private void loadConfig() {

worldedit-core/src/main/java/com/sk89q/worldedit/util/Java7Detector.java

@@ -18,21 +18,21 @@
  */
 package com.sk89q.worldedit.util;
 
-import com.google.common.base.Joiner;
 import com.sk89q.worldedit.WorldEdit;
 
-public final class Java8Detector {
+public final class Java7Detector {
 
     public static void notifyIfNot8() {
+        int major = -1;
+        try {
             String[] ver = System.getProperty("java.version").split("\\.");
-        int major = Integer.parseInt(ver[1]);
+            major = Integer.parseInt(ver[1]);
-        if (major <= 7) {
+        } catch (Exception ignored) {
-            // Implicitly java 7 because we compile against 7, so this won't
+        }
-            // even launch on 6.
+
+        if (major == 7) {
             WorldEdit.logger.warning(
-                    "WorldEdit has detected you are using Java 7"
+                    "WorldEdit has detected you are using Java 7.");
-                            + " (based on detected version "
-                            + Joiner.on('.').join(ver) + ").");
             WorldEdit.logger.warning(
                     "WorldEdit will stop supporting Java less than version 8 in the future,"
                             + " due to Java 7 being EOL since April 2015."
@@ -40,7 +40,7 @@ public final class Java8Detector {
         }
     }
 
-    private Java8Detector() {
+    private Java7Detector() {
     }
 
 }

worldedit-forge/src/main/java/com/sk89q/worldedit/forge/ForgeWorldEdit.java

@@ -30,7 +30,6 @@ import com.sk89q.worldedit.event.platform.PlatformReadyEvent;
 import com.sk89q.worldedit.extension.platform.Platform;
 import com.sk89q.worldedit.forge.net.LeftClickAirEventMessage;
 import com.sk89q.worldedit.internal.LocalWorldAdapter;
-import com.sk89q.worldedit.util.Java8Detector;
 
 import java.io.File;
 import java.util.Map;