1 files changed, 9 insertions, 22 deletions
diff --git a/java/core/src/main/java/com/google/protobuf/Descriptors.java b/java/core/src/main/java/com/google/protobuf/Descriptors.java
index 1c34c24f..cab7118a 100644
--- a/java/core/src/main/java/com/google/protobuf/Descriptors.java
+++ b/java/core/src/main/java/com/google/protobuf/Descriptors.java
@@ -1212,33 +1212,20 @@ public final class Descriptors {
       private final Object defaultDefault;
     }
 
-    // TODO(xiaofeng): Implement it consistently across different languages. See b/24751348.
-    private static String fieldNameToLowerCamelCase(String name) {
+    // This method should match exactly with the ToJsonName() function in C++
+    // descriptor.cc.
+    private static String fieldNameToJsonName(String name) {
       StringBuilder result = new StringBuilder(name.length());
       boolean isNextUpperCase = false;
       for (int i = 0; i < name.length(); i++) {
         Character ch = name.charAt(i);
-        if (Character.isLowerCase(ch)) {
-          if (isNextUpperCase) {
-            result.append(Character.toUpperCase(ch));
-          } else {
-            result.append(ch);
-          }
-          isNextUpperCase = false;
-        } else if (Character.isUpperCase(ch)) {
-          if (i == 0) {
-            // Force first letter to lower-case.
-            result.append(Character.toLowerCase(ch));
-          } else {
-            // Capital letters after the first are left as-is.
-            result.append(ch);
-          }
-          isNextUpperCase = false;
-        } else if (Character.isDigit(ch)) {
-          result.append(ch);
+        if (ch == '_') {
+          isNextUpperCase = true;
+        } else if (isNextUpperCase) {
+          result.append(Character.toUpperCase(ch));
           isNextUpperCase = false;
         } else {
-          isNextUpperCase = true;
+          result.append(ch);
         }
       }
       return result.toString();
@@ -1257,7 +1244,7 @@ public final class Descriptors {
       if (proto.hasJsonName()) {
         jsonName = proto.getJsonName();
       } else {
-        jsonName = fieldNameToLowerCamelCase(proto.getName());
+        jsonName = fieldNameToJsonName(proto.getName());
       }
 
       if (proto.hasType()) {