JAL-3235 override entrySet() to output Properties sorted by key (Java 9)

diff --git a/src/jalview/bin/Cache.java b/src/jalview/bin/Cache.java
index 19aa800..2bafb10 100755 (executable)
--- a/src/jalview/bin/Cache.java
+++ b/src/jalview/bin/Cache.java
@@ -43,8 +43,12 @@ import java.util.Collections;
 import java.util.Date;
 import java.util.Enumeration;
 import java.util.Locale;
+import java.util.Map;
+import java.util.Map.Entry;
 import java.util.Properties;
+import java.util.Set;
 import java.util.StringTokenizer;
+import java.util.TreeMap;
 import java.util.TreeSet;
 
 import org.apache.log4j.ConsoleAppender;
@@ -266,12 +270,24 @@ public class Cache
   /** Jalview Properties */
   public static Properties applicationProperties = new Properties()
   {
-    // override results in properties output in alphabetical order
+    // override so properties are output in alphabetical order (Java 8)
     @Override
     public synchronized Enumeration<Object> keys()
     {
       return Collections.enumeration(new TreeSet<>(super.keySet()));
     }
+
+    // override so properties are output in alphabetical order (Java 11)
+    @Override
+    public Set<Entry<Object, Object>> entrySet()
+    {
+      Map<Object, Object> copy = new TreeMap<>();
+      for (Object key : this.keySet())
+      {
+        copy.put(key, this.get(key));
+      }
+      return copy.entrySet();
+    }
   };
 
   /** Default file is ~/.jalview_properties */