.diff

diff --git a/core/src/main/java/org/jruby/RubyHash.java b/core/src/main/java/org/jruby/RubyHash.java
index f87c491604..39ccd4084b 100644
--- a/core/src/main/java/org/jruby/RubyHash.java
+++ b/core/src/main/java/org/jruby/RubyHash.java
@@ -2162,8 +2162,7 @@ public class RubyHash extends RubyObject implements Map {
 
         if (this == otherHash) return this;
 
-        alloc();
-        copyFrom(this, otherHash, otherHash.isComparedByIdentity());
+        replaceWith(context, otherHash);
 
         ifNone = otherHash.ifNone;
 
@@ -2176,6 +2175,25 @@ public class RubyHash extends RubyObject implements Map {
         return this;
     }
 
+    protected void replaceWith(ThreadContext context, RubyHash otherHash) {
+        if (otherHash.getClass() == RubyHash.class) {
+            alloc();
+            copyFrom(this, otherHash, otherHash.isComparedByIdentity());
+        } else {
+            replaceExternally(context, otherHash);
+        }
+    }
+
+    protected void replaceExternally(ThreadContext context, RubyHash otherHash) {
+        rb_clear(context);
+
+        if (!isComparedByIdentity() && otherHash.isComparedByIdentity()) {
+            setComparedByIdentity(true);
+        }
+
+        otherHash.visitAll(context, ReplaceVisitor, this);
+    }
+
     private static final VisitorWithState<RubyHash> ReplaceVisitor = new VisitorWithState<RubyHash>() {
         @Override
         public void visit(ThreadContext context, RubyHash self, IRubyObject key, IRubyObject value, int index, RubyHash target) {
diff --git a/core/src/main/java/org/jruby/java/proxies/MapJavaProxy.java b/core/src/main/java/org/jruby/java/proxies/MapJavaProxy.java
index 5503fc1a31..b3ba23ed94 100644
--- a/core/src/main/java/org/jruby/java/proxies/MapJavaProxy.java
+++ b/core/src/main/java/org/jruby/java/proxies/MapJavaProxy.java
@@ -385,6 +385,11 @@ public final class MapJavaProxy extends ConcreteJavaProxy {
         @Override
         public final Set directEntrySet() { return entrySet(); }
 
+        @Override
+        protected void replaceWith(ThreadContext context, RubyHash otherHash) {
+            replaceExternally(context, otherHash);
+        }
+
     }
 
     @JRubyMethod(name = "default")