1 files changed, 16 insertions, 1 deletions
diff --git a/java/src/main/java/com/google/protobuf/nano/FieldArray.java b/java/src/main/java/com/google/protobuf/nano/FieldArray.java
index ab923a4..473c161 100644
--- a/java/src/main/java/com/google/protobuf/nano/FieldArray.java
+++ b/java/src/main/java/com/google/protobuf/nano/FieldArray.java
@@ -37,7 +37,7 @@ package com.google.protobuf.nano;
  *
  * Based on {@link android.support.v4.util.SpareArrayCompat}.
  */
-class FieldArray {
+class FieldArray implements Cloneable {
     private static final FieldData DELETED = new FieldData();
     private boolean mGarbage = false;
 
@@ -270,4 +270,19 @@ class FieldArray {
         }
         return true;
     }
+
+    @Override
+    public final FieldArray clone() {
+        // Trigger GC so we compact and don't copy DELETED elements.
+        int size = size();
+        FieldArray clone = new FieldArray(size);
+        System.arraycopy(mFieldNumbers, 0, clone.mFieldNumbers, 0, size);
+        for (int i = 0; i < size; i++) {
+            if (mData[i] != null) {
+                clone.mData[i] = mData[i].clone();
+            }
+        }
+        clone.mSize = size;
+        return clone;
+    }
 }