diff --git a/icu4c/source/common/propname.h b/icu4c/source/common/propname.h
index 400838f0ce..d762af52e5 100644
--- a/icu4c/source/common/propname.h
+++ b/icu4c/source/common/propname.h
@@ -89,6 +89,7 @@ class PropertyAliases {
 
     // The following are needed by external readers of this data.
     // We don't use them ourselves.
+    int16_t total_size; // size in bytes excluding the udata header
     Offset valueMap_offset; // offset to start of array
     int16_t valueMap_count; // number of entries
     Offset nameGroupPool_offset; // offset to start of array
@@ -96,8 +97,6 @@ class PropertyAliases {
     Offset stringPool_offset; // offset to start of pool
     int16_t stringPool_count; // number of strings
 
-    int16_t reserved;
-
     // -- end pnames data --
 
     friend class Builder;
diff --git a/icu4c/source/tools/genpname/genpname.cpp b/icu4c/source/tools/genpname/genpname.cpp
index 8d908a0c0a..2284c480b4 100644
--- a/icu4c/source/tools/genpname/genpname.cpp
+++ b/icu4c/source/tools/genpname/genpname.cpp
@@ -784,6 +784,9 @@ void Builder::fixupMiscellaneousOffsets() {
     header.enumToName_offset = enumToName_offset;
     header.nameToEnum_offset = nameToEnum_offset;
     header.enumToValue_offset = enumToValue_offset;
+    // header meta-info used by Java:
+	U_ASSERT(total_size > 0 && total_size < 0x7FFF);
+    header.total_size = (int16_t) total_size;
     header.valueMap_offset = valueMap_offset;
     header.valueMap_count = (int16_t) valueMap_count;
     header.nameGroupPool_offset = nameGroupPool_offset;