diff --git a/core/config_sanitizers.mk b/core/config_sanitizers.mk
index aa638d4..d837c6e 100644
--- a/core/config_sanitizers.mk
+++ b/core/config_sanitizers.mk
@@ -249,6 +249,13 @@
   endif
 endif
 
+# Ignore SANITIZE_TARGET_DIAG=memtag_heap without SANITIZE_TARGET=memtag_heap
+# This can happen if a condition above filters out memtag_heap from
+# my_sanitize. It is easier to handle all of these cases here centrally.
+ifneq ($(filter memtag_heap,$(my_sanitize_diag)),)
+  my_sanitize_diag := $(filter-out memtag_heap,$(my_sanitize_diag))
+endif
+
 ifneq ($(filter memtag_heap,$(my_sanitize)),)
   my_cflags += -fsanitize=memtag-heap
   my_sanitize := $(filter-out memtag_heap,$(my_sanitize))
diff --git a/tools/aconfig/Android.bp b/tools/aconfig/Android.bp
index 9617e0e..b8cce29 100644
--- a/tools/aconfig/Android.bp
+++ b/tools/aconfig/Android.bp
@@ -35,4 +35,7 @@
 rust_test_host {
     name: "aconfig.test",
     defaults: ["aconfig.defaults"],
+    rustlibs: [
+        "libitertools",
+    ],
 }
diff --git a/tools/aconfig/Cargo.toml b/tools/aconfig/Cargo.toml
index 8517dd2..b3c73b8 100644
--- a/tools/aconfig/Cargo.toml
+++ b/tools/aconfig/Cargo.toml
@@ -18,3 +18,6 @@
 
 [build-dependencies]
 protobuf-codegen = "3.2.0"
+
+[dev-dependencies]
+itertools = "0.10.5"
diff --git a/tools/aconfig/protos/aconfig.proto b/tools/aconfig/protos/aconfig.proto
index 9d36a9e..9f6424f 100644
--- a/tools/aconfig/protos/aconfig.proto
+++ b/tools/aconfig/protos/aconfig.proto
@@ -36,16 +36,17 @@
 
 message flag_declaration {
   required string name = 1;
-  required string description = 2;
+  required string namespace = 2;
+  required string description = 3;
 };
 
 message flag_declarations {
-  required string namespace = 1;
+  required string package = 1;
   repeated flag_declaration flag = 2;
 };
 
 message flag_value {
-  required string namespace = 1;
+  required string package = 1;
   required string name = 2;
   required flag_state state = 3;
   required flag_permission permission = 4;
@@ -65,12 +66,13 @@
 }
 
 message parsed_flag {
-  required string namespace = 1;
+  required string package = 1;
   required string name = 2;
-  required string description = 3;
-  required flag_state state = 4;
-  required flag_permission permission = 5;
-  repeated tracepoint trace = 6;
+  required string namespace = 3;
+  required string description = 4;
+  required flag_state state = 5;
+  required flag_permission permission = 6;
+  repeated tracepoint trace = 7;
 }
 
 message parsed_flags {
diff --git a/tools/aconfig/src/aconfig.rs b/tools/aconfig/src/aconfig.rs
index b9fa324..5e7c861 100644
--- a/tools/aconfig/src/aconfig.rs
+++ b/tools/aconfig/src/aconfig.rs
@@ -81,6 +81,7 @@
 #[derive(Debug, PartialEq, Eq)]
 pub struct FlagDeclaration {
     pub name: String,
+    pub namespace: String,
     pub description: String,
 }
 
@@ -100,16 +101,19 @@
         let Some(name) = proto.name else {
             bail!("missing 'name' field");
         };
+        let Some(namespace) = proto.namespace else {
+            bail!("missing 'namespace' field");
+        };
         let Some(description) = proto.description else {
             bail!("missing 'description' field");
         };
-        Ok(FlagDeclaration { name, description })
+        Ok(FlagDeclaration { name, namespace, description })
     }
 }
 
 #[derive(Debug, PartialEq, Eq)]
 pub struct FlagDeclarations {
-    pub namespace: String,
+    pub package: String,
     pub flags: Vec<FlagDeclaration>,
 }
 
@@ -117,20 +121,20 @@
     pub fn try_from_text_proto(text_proto: &str) -> Result<FlagDeclarations> {
         let proto: ProtoFlagDeclarations = crate::protos::try_from_text_proto(text_proto)
             .with_context(|| text_proto.to_owned())?;
-        let Some(namespace) = proto.namespace else {
-            bail!("missing 'namespace' field");
+        let Some(package) = proto.package else {
+            bail!("missing 'package' field");
         };
         let mut flags = vec![];
         for proto_flag in proto.flag.into_iter() {
             flags.push(proto_flag.try_into()?);
         }
-        Ok(FlagDeclarations { namespace, flags })
+        Ok(FlagDeclarations { package, flags })
     }
 }
 
 #[derive(Debug, PartialEq, Eq)]
 pub struct FlagValue {
-    pub namespace: String,
+    pub package: String,
     pub name: String,
     pub state: FlagState,
     pub permission: Permission,
@@ -153,8 +157,8 @@
     type Error = Error;
 
     fn try_from(proto: ProtoFlagValue) -> Result<Self, Self::Error> {
-        let Some(namespace) = proto.namespace else {
-            bail!("missing 'namespace' field");
+        let Some(package) = proto.package else {
+            bail!("missing 'package' field");
         };
         let Some(name) = proto.name else {
             bail!("missing 'name' field");
@@ -167,7 +171,7 @@
             bail!("missing 'permission' field");
         };
         let permission = proto_permission.try_into()?;
-        Ok(FlagValue { namespace, name, state, permission })
+        Ok(FlagValue { package, name, state, permission })
     }
 }
 
@@ -184,8 +188,9 @@
 impl From<Item> for ProtoParsedFlag {
     fn from(item: Item) -> Self {
         let mut proto = crate::protos::ProtoParsedFlag::new();
-        proto.set_namespace(item.namespace.to_owned());
+        proto.set_package(item.package.to_owned());
         proto.set_name(item.name.clone());
+        proto.set_namespace(item.namespace.clone());
         proto.set_description(item.description.clone());
         proto.set_state(item.state.into());
         proto.set_permission(item.permission.into());
@@ -214,11 +219,13 @@
     fn test_flag_try_from_text_proto() {
         let expected = FlagDeclaration {
             name: "1234".to_owned(),
+            namespace: "ns".to_owned(),
             description: "Description of the flag".to_owned(),
         };
 
         let s = r#"
         name: "1234"
+        namespace: "ns"
         description: "Description of the flag"
         "#;
         let actual = FlagDeclaration::try_from_text_proto(s).unwrap();
@@ -242,23 +249,33 @@
     }
 
     #[test]
-    fn test_namespace_try_from_text_proto() {
+    fn test_package_try_from_text_proto() {
         let expected = FlagDeclarations {
-            namespace: "ns".to_owned(),
+            package: "com.example".to_owned(),
             flags: vec![
-                FlagDeclaration { name: "a".to_owned(), description: "A".to_owned() },
-                FlagDeclaration { name: "b".to_owned(), description: "B".to_owned() },
+                FlagDeclaration {
+                    name: "a".to_owned(),
+                    namespace: "ns".to_owned(),
+                    description: "A".to_owned(),
+                },
+                FlagDeclaration {
+                    name: "b".to_owned(),
+                    namespace: "ns".to_owned(),
+                    description: "B".to_owned(),
+                },
             ],
         };
 
         let s = r#"
-        namespace: "ns"
+        package: "com.example"
         flag {
             name: "a"
+            namespace: "ns"
             description: "A"
         }
         flag {
             name: "b"
+            namespace: "ns"
             description: "B"
         }
         "#;
@@ -270,14 +287,14 @@
     #[test]
     fn test_flag_declaration_try_from_text_proto_list() {
         let expected = FlagValue {
-            namespace: "ns".to_owned(),
+            package: "com.example".to_owned(),
             name: "1234".to_owned(),
             state: FlagState::Enabled,
             permission: Permission::ReadOnly,
         };
 
         let s = r#"
-        namespace: "ns"
+        package: "com.example"
         name: "1234"
         state: ENABLED
         permission: READ_ONLY
diff --git a/tools/aconfig/src/cache.rs b/tools/aconfig/src/cache.rs
index 972ba41..dd54480 100644
--- a/tools/aconfig/src/cache.rs
+++ b/tools/aconfig/src/cache.rs
@@ -34,12 +34,13 @@
 
 #[derive(Serialize, Deserialize, Debug)]
 pub struct Item {
-    // TODO: duplicating the Cache.namespace as Item.namespace makes the internal representation
+    // TODO: duplicating the Cache.package as Item.package makes the internal representation
     // closer to the proto message `parsed_flag`; hopefully this will enable us to replace the Item
-    // struct and use a newtype instead once aconfig has matured. Until then, namespace should
+    // struct and use a newtype instead once aconfig has matured. Until then, package should
     // really be a Cow<String>.
-    pub namespace: String,
+    pub package: String,
     pub name: String,
+    pub namespace: String,
     pub description: String,
     pub state: FlagState,
     pub permission: Permission,
@@ -48,7 +49,7 @@
 
 #[derive(Serialize, Deserialize, Debug)]
 pub struct Cache {
-    namespace: String,
+    package: String,
     items: Vec<Item>,
 }
 
@@ -96,9 +97,9 @@
         self.items.into_iter()
     }
 
-    pub fn namespace(&self) -> &str {
-        debug_assert!(!self.namespace.is_empty());
-        &self.namespace
+    pub fn package(&self) -> &str {
+        debug_assert!(!self.package.is_empty());
+        &self.package
     }
 }
 
@@ -108,9 +109,9 @@
 }
 
 impl CacheBuilder {
-    pub fn new(namespace: String) -> Result<CacheBuilder> {
-        ensure!(codegen::is_valid_identifier(&namespace), "bad namespace");
-        let cache = Cache { namespace, items: vec![] };
+    pub fn new(package: String) -> Result<CacheBuilder> {
+        ensure!(codegen::is_valid_package_ident(&package), "bad package");
+        let cache = Cache { package, items: vec![] };
         Ok(CacheBuilder { cache })
     }
 
@@ -119,7 +120,8 @@
         source: Source,
         declaration: FlagDeclaration,
     ) -> Result<&mut CacheBuilder> {
-        ensure!(codegen::is_valid_identifier(&declaration.name), "bad flag name");
+        ensure!(codegen::is_valid_name_ident(&declaration.name), "bad flag name");
+        ensure!(codegen::is_valid_name_ident(&declaration.namespace), "bad namespace");
         ensure!(!declaration.description.is_empty(), "empty flag description");
         ensure!(
             self.cache.items.iter().all(|item| item.name != declaration.name),
@@ -128,8 +130,9 @@
             source
         );
         self.cache.items.push(Item {
-            namespace: self.cache.namespace.clone(),
+            package: self.cache.package.clone(),
             name: declaration.name.clone(),
+            namespace: declaration.namespace.clone(),
             description: declaration.description,
             state: DEFAULT_FLAG_STATE,
             permission: DEFAULT_FLAG_PERMISSION,
@@ -147,18 +150,18 @@
         source: Source,
         value: FlagValue,
     ) -> Result<&mut CacheBuilder> {
-        ensure!(codegen::is_valid_identifier(&value.namespace), "bad flag namespace");
-        ensure!(codegen::is_valid_identifier(&value.name), "bad flag name");
+        ensure!(codegen::is_valid_package_ident(&value.package), "bad flag package");
+        ensure!(codegen::is_valid_name_ident(&value.name), "bad flag name");
         ensure!(
-            value.namespace == self.cache.namespace,
-            "failed to set values for flag {}/{} from {}: expected namespace {}",
-            value.namespace,
+            value.package == self.cache.package,
+            "failed to set values for flag {}/{} from {}: expected package {}",
+            value.package,
             value.name,
             source,
-            self.cache.namespace
+            self.cache.package
         );
         let Some(existing_item) = self.cache.items.iter_mut().find(|item| item.name == value.name) else {
-            bail!("failed to set values for flag {}/{} from {}: flag not declared", value.namespace, value.name, source);
+            bail!("failed to set values for flag {}/{} from {}: flag not declared", value.package, value.name, source);
         };
         existing_item.state = value.state;
         existing_item.permission = value.permission;
@@ -182,17 +185,25 @@
 
     #[test]
     fn test_add_flag_declaration() {
-        let mut builder = CacheBuilder::new("ns".to_string()).unwrap();
+        let mut builder = CacheBuilder::new("com.example".to_string()).unwrap();
         builder
             .add_flag_declaration(
                 Source::File("first.txt".to_string()),
-                FlagDeclaration { name: "foo".to_string(), description: "desc".to_string() },
+                FlagDeclaration {
+                    name: "foo".to_string(),
+                    namespace: "ns".to_string(),
+                    description: "desc".to_string(),
+                },
             )
             .unwrap();
         let error = builder
             .add_flag_declaration(
                 Source::File("second.txt".to_string()),
-                FlagDeclaration { name: "foo".to_string(), description: "desc".to_string() },
+                FlagDeclaration {
+                    name: "foo".to_string(),
+                    namespace: "ns".to_string(),
+                    description: "desc".to_string(),
+                },
             )
             .unwrap_err();
         assert_eq!(
@@ -202,7 +213,11 @@
         builder
             .add_flag_declaration(
                 Source::File("first.txt".to_string()),
-                FlagDeclaration { name: "bar".to_string(), description: "desc".to_string() },
+                FlagDeclaration {
+                    name: "bar".to_string(),
+                    namespace: "ns".to_string(),
+                    description: "desc".to_string(),
+                },
             )
             .unwrap();
 
@@ -217,12 +232,12 @@
 
     #[test]
     fn test_add_flag_value() {
-        let mut builder = CacheBuilder::new("ns".to_string()).unwrap();
+        let mut builder = CacheBuilder::new("com.example".to_string()).unwrap();
         let error = builder
             .add_flag_value(
                 Source::Memory,
                 FlagValue {
-                    namespace: "ns".to_string(),
+                    package: "com.example".to_string(),
                     name: "foo".to_string(),
                     state: FlagState::Enabled,
                     permission: Permission::ReadOnly,
@@ -231,13 +246,17 @@
             .unwrap_err();
         assert_eq!(
             &format!("{:?}", error),
-            "failed to set values for flag ns/foo from <memory>: flag not declared"
+            "failed to set values for flag com.example/foo from <memory>: flag not declared"
         );
 
         builder
             .add_flag_declaration(
                 Source::File("first.txt".to_string()),
-                FlagDeclaration { name: "foo".to_string(), description: "desc".to_string() },
+                FlagDeclaration {
+                    name: "foo".to_string(),
+                    namespace: "ns".to_string(),
+                    description: "desc".to_string(),
+                },
             )
             .unwrap();
 
@@ -245,7 +264,7 @@
             .add_flag_value(
                 Source::Memory,
                 FlagValue {
-                    namespace: "ns".to_string(),
+                    package: "com.example".to_string(),
                     name: "foo".to_string(),
                     state: FlagState::Disabled,
                     permission: Permission::ReadOnly,
@@ -257,7 +276,7 @@
             .add_flag_value(
                 Source::Memory,
                 FlagValue {
-                    namespace: "ns".to_string(),
+                    package: "com.example".to_string(),
                     name: "foo".to_string(),
                     state: FlagState::Enabled,
                     permission: Permission::ReadWrite,
@@ -265,19 +284,19 @@
             )
             .unwrap();
 
-        // different namespace -> no-op
+        // different package -> no-op
         let error = builder
             .add_flag_value(
                 Source::Memory,
                 FlagValue {
-                    namespace: "some_other_namespace".to_string(),
+                    package: "some_other_package".to_string(),
                     name: "foo".to_string(),
                     state: FlagState::Enabled,
                     permission: Permission::ReadOnly,
                 },
             )
             .unwrap_err();
-        assert_eq!(&format!("{:?}", error), "failed to set values for flag some_other_namespace/foo from <memory>: expected namespace ns");
+        assert_eq!(&format!("{:?}", error), "failed to set values for flag some_other_package/foo from <memory>: expected package com.example");
 
         let cache = builder.build();
         let item = cache.iter().find(|&item| item.name == "foo").unwrap();
@@ -286,18 +305,22 @@
     }
 
     #[test]
-    fn test_reject_empty_cache_namespace() {
+    fn test_reject_empty_cache_package() {
         CacheBuilder::new("".to_string()).unwrap_err();
     }
 
     #[test]
     fn test_reject_empty_flag_declaration_fields() {
-        let mut builder = CacheBuilder::new("ns".to_string()).unwrap();
+        let mut builder = CacheBuilder::new("com.example".to_string()).unwrap();
 
         let error = builder
             .add_flag_declaration(
                 Source::Memory,
-                FlagDeclaration { name: "".to_string(), description: "Description".to_string() },
+                FlagDeclaration {
+                    name: "".to_string(),
+                    namespace: "ns".to_string(),
+                    description: "Description".to_string(),
+                },
             )
             .unwrap_err();
         assert_eq!(&format!("{:?}", error), "bad flag name");
@@ -305,7 +328,11 @@
         let error = builder
             .add_flag_declaration(
                 Source::Memory,
-                FlagDeclaration { name: "foo".to_string(), description: "".to_string() },
+                FlagDeclaration {
+                    name: "foo".to_string(),
+                    namespace: "ns".to_string(),
+                    description: "".to_string(),
+                },
             )
             .unwrap_err();
         assert_eq!(&format!("{:?}", error), "empty flag description");
@@ -313,11 +340,15 @@
 
     #[test]
     fn test_reject_empty_flag_value_files() {
-        let mut builder = CacheBuilder::new("ns".to_string()).unwrap();
+        let mut builder = CacheBuilder::new("com.example".to_string()).unwrap();
         builder
             .add_flag_declaration(
                 Source::Memory,
-                FlagDeclaration { name: "foo".to_string(), description: "desc".to_string() },
+                FlagDeclaration {
+                    name: "foo".to_string(),
+                    namespace: "ns".to_string(),
+                    description: "desc".to_string(),
+                },
             )
             .unwrap();
 
@@ -325,20 +356,20 @@
             .add_flag_value(
                 Source::Memory,
                 FlagValue {
-                    namespace: "".to_string(),
+                    package: "".to_string(),
                     name: "foo".to_string(),
                     state: FlagState::Enabled,
                     permission: Permission::ReadOnly,
                 },
             )
             .unwrap_err();
-        assert_eq!(&format!("{:?}", error), "bad flag namespace");
+        assert_eq!(&format!("{:?}", error), "bad flag package");
 
         let error = builder
             .add_flag_value(
                 Source::Memory,
                 FlagValue {
-                    namespace: "ns".to_string(),
+                    package: "com.example".to_string(),
                     name: "".to_string(),
                     state: FlagState::Enabled,
                     permission: Permission::ReadOnly,
diff --git a/tools/aconfig/src/codegen.rs b/tools/aconfig/src/codegen.rs
index b60ec51..fea9961 100644
--- a/tools/aconfig/src/codegen.rs
+++ b/tools/aconfig/src/codegen.rs
@@ -14,7 +14,9 @@
  * limitations under the License.
  */
 
-pub fn is_valid_identifier(s: &str) -> bool {
+use anyhow::{ensure, Result};
+
+pub fn is_valid_name_ident(s: &str) -> bool {
     // Identifiers must match [a-z][a-z0-9_]*
     let mut chars = s.chars();
     let Some(first) = chars.next() else {
@@ -26,18 +28,54 @@
     chars.all(|ch| ch.is_ascii_lowercase() || ch.is_ascii_digit() || ch == '_')
 }
 
+pub fn is_valid_package_ident(s: &str) -> bool {
+    s.split('.').all(is_valid_name_ident)
+}
+
+pub fn create_device_config_ident(package: &str, flag_name: &str) -> Result<String> {
+    ensure!(is_valid_package_ident(package), "bad package");
+    ensure!(is_valid_package_ident(flag_name), "bad flag name");
+    Ok(format!("{}.{}", package, flag_name))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
     #[test]
-    fn test_is_valid_identifier() {
-        assert!(is_valid_identifier("foo"));
-        assert!(is_valid_identifier("foo_bar_123"));
+    fn test_is_valid_name_ident() {
+        assert!(is_valid_name_ident("foo"));
+        assert!(is_valid_name_ident("foo_bar_123"));
 
-        assert!(!is_valid_identifier(""));
-        assert!(!is_valid_identifier("123_foo"));
-        assert!(!is_valid_identifier("foo-bar"));
-        assert!(!is_valid_identifier("foo-b\u{00e5}r"));
+        assert!(!is_valid_name_ident(""));
+        assert!(!is_valid_name_ident("123_foo"));
+        assert!(!is_valid_name_ident("foo-bar"));
+        assert!(!is_valid_name_ident("foo-b\u{00e5}r"));
+    }
+
+    #[test]
+    fn test_is_valid_package_ident() {
+        assert!(is_valid_package_ident("foo"));
+        assert!(is_valid_package_ident("foo_bar_123"));
+        assert!(is_valid_package_ident("foo.bar"));
+        assert!(is_valid_package_ident("foo.bar.a123"));
+
+        assert!(!is_valid_package_ident(""));
+        assert!(!is_valid_package_ident("123_foo"));
+        assert!(!is_valid_package_ident("foo-bar"));
+        assert!(!is_valid_package_ident("foo-b\u{00e5}r"));
+        assert!(!is_valid_package_ident("foo.bar.123"));
+        assert!(!is_valid_package_ident(".foo.bar"));
+        assert!(!is_valid_package_ident("foo.bar."));
+        assert!(!is_valid_package_ident("."));
+        assert!(!is_valid_package_ident("foo..bar"));
+    }
+
+    #[test]
+    fn test_create_device_config_ident() {
+        assert_eq!(
+            "com.foo.bar.some_flag",
+            create_device_config_ident("com.foo.bar", "some_flag").unwrap()
+        );
     }
 }
diff --git a/tools/aconfig/src/codegen_cpp.rs b/tools/aconfig/src/codegen_cpp.rs
index 2aeea6a..2c32bb0 100644
--- a/tools/aconfig/src/codegen_cpp.rs
+++ b/tools/aconfig/src/codegen_cpp.rs
@@ -14,29 +14,42 @@
  * limitations under the License.
  */
 
-use anyhow::Result;
+use anyhow::{ensure, Result};
 use serde::Serialize;
 use tinytemplate::TinyTemplate;
 
 use crate::aconfig::{FlagState, Permission};
 use crate::cache::{Cache, Item};
+use crate::codegen;
 use crate::commands::OutputFile;
 
 pub fn generate_cpp_code(cache: &Cache) -> Result<OutputFile> {
-    let class_elements: Vec<ClassElement> = cache.iter().map(create_class_element).collect();
+    let package = cache.package();
+    let class_elements: Vec<ClassElement> =
+        cache.iter().map(|item| create_class_element(package, item)).collect();
     let readwrite = class_elements.iter().any(|item| item.readwrite);
-    let namespace = cache.namespace().to_lowercase();
-    let context = Context { namespace: namespace.clone(), readwrite, class_elements };
+    let header = package.replace('.', "_");
+    let cpp_namespace = package.replace('.', "::");
+    ensure!(codegen::is_valid_name_ident(&header));
+    let context = Context {
+        header: header.clone(),
+        cpp_namespace,
+        package: package.to_string(),
+        readwrite,
+        class_elements,
+    };
     let mut template = TinyTemplate::new();
     template.add_template("cpp_code_gen", include_str!("../templates/cpp.template"))?;
     let contents = template.render("cpp_code_gen", &context)?;
-    let path = ["aconfig", &(namespace + ".h")].iter().collect();
+    let path = ["aconfig", &(header + ".h")].iter().collect();
     Ok(OutputFile { contents: contents.into(), path })
 }
 
 #[derive(Serialize)]
 struct Context {
-    pub namespace: String,
+    pub header: String,
+    pub cpp_namespace: String,
+    pub package: String,
     pub readwrite: bool,
     pub class_elements: Vec<ClassElement>,
 }
@@ -46,9 +59,11 @@
     pub readwrite: bool,
     pub default_value: String,
     pub flag_name: String,
+    pub device_config_namespace: String,
+    pub device_config_flag: String,
 }
 
-fn create_class_element(item: &Item) -> ClassElement {
+fn create_class_element(package: &str, item: &Item) -> ClassElement {
     ClassElement {
         readwrite: item.permission == Permission::ReadWrite,
         default_value: if item.state == FlagState::Enabled {
@@ -57,6 +72,9 @@
             "false".to_string()
         },
         flag_name: item.name.clone(),
+        device_config_namespace: item.namespace.to_string(),
+        device_config_flag: codegen::create_device_config_ident(package, &item.name)
+            .expect("values checked at cache creation time"),
     }
 }
 
@@ -69,13 +87,14 @@
 
     #[test]
     fn test_cpp_codegen_build_time_flag_only() {
-        let namespace = "my_namespace";
-        let mut builder = CacheBuilder::new(namespace.to_string()).unwrap();
+        let package = "com.example";
+        let mut builder = CacheBuilder::new(package.to_string()).unwrap();
         builder
             .add_flag_declaration(
                 Source::File("aconfig_one.txt".to_string()),
                 FlagDeclaration {
                     name: "my_flag_one".to_string(),
+                    namespace: "ns".to_string(),
                     description: "buildtime disable".to_string(),
                 },
             )
@@ -83,7 +102,7 @@
             .add_flag_value(
                 Source::Memory,
                 FlagValue {
-                    namespace: namespace.to_string(),
+                    package: package.to_string(),
                     name: "my_flag_one".to_string(),
                     state: FlagState::Disabled,
                     permission: Permission::ReadOnly,
@@ -94,6 +113,7 @@
                 Source::File("aconfig_two.txt".to_string()),
                 FlagDeclaration {
                     name: "my_flag_two".to_string(),
+                    namespace: "ns".to_string(),
                     description: "buildtime enable".to_string(),
                 },
             )
@@ -101,7 +121,7 @@
             .add_flag_value(
                 Source::Memory,
                 FlagValue {
-                    namespace: namespace.to_string(),
+                    package: package.to_string(),
                     name: "my_flag_two".to_string(),
                     state: FlagState::Enabled,
                     permission: Permission::ReadOnly,
@@ -109,11 +129,10 @@
             )
             .unwrap();
         let cache = builder.build();
-        let expect_content = r#"#ifndef my_namespace_HEADER_H
-        #define my_namespace_HEADER_H
-        #include "my_namespace.h"
+        let expect_content = r#"#ifndef com_example_HEADER_H
+        #define com_example_HEADER_H
 
-        namespace my_namespace {
+        namespace com::example {
 
             class my_flag_one {
                 public:
@@ -133,7 +152,7 @@
         #endif
         "#;
         let file = generate_cpp_code(&cache).unwrap();
-        assert_eq!("aconfig/my_namespace.h", file.path.to_str().unwrap());
+        assert_eq!("aconfig/com_example.h", file.path.to_str().unwrap());
         assert_eq!(
             expect_content.replace(' ', ""),
             String::from_utf8(file.contents).unwrap().replace(' ', "")
@@ -142,13 +161,14 @@
 
     #[test]
     fn test_cpp_codegen_runtime_flag() {
-        let namespace = "my_namespace";
-        let mut builder = CacheBuilder::new(namespace.to_string()).unwrap();
+        let package = "com.example";
+        let mut builder = CacheBuilder::new(package.to_string()).unwrap();
         builder
             .add_flag_declaration(
                 Source::File("aconfig_one.txt".to_string()),
                 FlagDeclaration {
                     name: "my_flag_one".to_string(),
+                    namespace: "ns".to_string(),
                     description: "buildtime disable".to_string(),
                 },
             )
@@ -157,6 +177,7 @@
                 Source::File("aconfig_two.txt".to_string()),
                 FlagDeclaration {
                     name: "my_flag_two".to_string(),
+                    namespace: "ns".to_string(),
                     description: "runtime enable".to_string(),
                 },
             )
@@ -164,7 +185,7 @@
             .add_flag_value(
                 Source::Memory,
                 FlagValue {
-                    namespace: namespace.to_string(),
+                    package: package.to_string(),
                     name: "my_flag_two".to_string(),
                     state: FlagState::Enabled,
                     permission: Permission::ReadWrite,
@@ -172,21 +193,20 @@
             )
             .unwrap();
         let cache = builder.build();
-        let expect_content = r#"#ifndef my_namespace_HEADER_H
-        #define my_namespace_HEADER_H
-        #include "my_namespace.h"
+        let expect_content = r#"#ifndef com_example_HEADER_H
+        #define com_example_HEADER_H
 
         #include <server_configurable_flags/get_flags.h>
         using namespace server_configurable_flags;
 
-        namespace my_namespace {
+        namespace com::example {
 
             class my_flag_one {
                 public:
                     virtual const bool value() {
                         return GetServerConfigurableFlag(
-                            "my_namespace",
-                            "my_flag_one",
+                            "ns",
+                            "com.example.my_flag_one",
                             "false") == "true";
                     }
             }
@@ -195,8 +215,8 @@
                 public:
                     virtual const bool value() {
                         return GetServerConfigurableFlag(
-                            "my_namespace",
-                            "my_flag_two",
+                            "ns",
+                            "com.example.my_flag_two",
                             "true") == "true";
                     }
             }
@@ -205,10 +225,13 @@
         #endif
         "#;
         let file = generate_cpp_code(&cache).unwrap();
-        assert_eq!("aconfig/my_namespace.h", file.path.to_str().unwrap());
+        assert_eq!("aconfig/com_example.h", file.path.to_str().unwrap());
         assert_eq!(
-            expect_content.replace(' ', ""),
-            String::from_utf8(file.contents).unwrap().replace(' ', "")
+            None,
+            crate::test::first_significant_code_diff(
+                expect_content,
+                &String::from_utf8(file.contents).unwrap()
+            )
         );
     }
 }
diff --git a/tools/aconfig/src/codegen_java.rs b/tools/aconfig/src/codegen_java.rs
index 98288e7..dfd6766 100644
--- a/tools/aconfig/src/codegen_java.rs
+++ b/tools/aconfig/src/codegen_java.rs
@@ -21,17 +21,19 @@
 
 use crate::aconfig::{FlagState, Permission};
 use crate::cache::{Cache, Item};
+use crate::codegen;
 use crate::commands::OutputFile;
 
 pub fn generate_java_code(cache: &Cache) -> Result<OutputFile> {
-    let class_elements: Vec<ClassElement> = cache.iter().map(create_class_element).collect();
+    let package = cache.package();
+    let class_elements: Vec<ClassElement> =
+        cache.iter().map(|item| create_class_element(package, item)).collect();
     let readwrite = class_elements.iter().any(|item| item.readwrite);
-    let namespace = cache.namespace();
-    let context = Context { namespace: namespace.to_string(), readwrite, class_elements };
+    let context = Context { package: package.to_string(), readwrite, class_elements };
     let mut template = TinyTemplate::new();
     template.add_template("java_code_gen", include_str!("../templates/java.template"))?;
     let contents = template.render("java_code_gen", &context)?;
-    let mut path: PathBuf = ["aconfig", namespace].iter().collect();
+    let mut path: PathBuf = package.split('.').collect();
     // TODO: Allow customization of the java class name
     path.push("Flags.java");
     Ok(OutputFile { contents: contents.into(), path })
@@ -39,7 +41,7 @@
 
 #[derive(Serialize)]
 struct Context {
-    pub namespace: String,
+    pub package: String,
     pub readwrite: bool,
     pub class_elements: Vec<ClassElement>,
 }
@@ -49,11 +51,13 @@
     pub method_name: String,
     pub readwrite: bool,
     pub default_value: String,
-    pub feature_name: String,
-    pub flag_name: String,
+    pub device_config_namespace: String,
+    pub device_config_flag: String,
 }
 
-fn create_class_element(item: &Item) -> ClassElement {
+fn create_class_element(package: &str, item: &Item) -> ClassElement {
+    let device_config_flag = codegen::create_device_config_ident(package, &item.name)
+        .expect("values checked at cache creation time");
     ClassElement {
         method_name: item.name.clone(),
         readwrite: item.permission == Permission::ReadWrite,
@@ -62,8 +66,8 @@
         } else {
             "false".to_string()
         },
-        feature_name: item.name.clone(),
-        flag_name: item.name.clone(),
+        device_config_namespace: item.namespace.clone(),
+        device_config_flag,
     }
 }
 
@@ -76,13 +80,14 @@
 
     #[test]
     fn test_generate_java_code() {
-        let namespace = "example";
-        let mut builder = CacheBuilder::new(namespace.to_string()).unwrap();
+        let package = "com.example";
+        let mut builder = CacheBuilder::new(package.to_string()).unwrap();
         builder
             .add_flag_declaration(
                 Source::File("test.txt".to_string()),
                 FlagDeclaration {
                     name: "test".to_string(),
+                    namespace: "ns".to_string(),
                     description: "buildtime enable".to_string(),
                 },
             )
@@ -91,6 +96,7 @@
                 Source::File("test2.txt".to_string()),
                 FlagDeclaration {
                     name: "test2".to_string(),
+                    namespace: "ns".to_string(),
                     description: "runtime disable".to_string(),
                 },
             )
@@ -98,7 +104,7 @@
             .add_flag_value(
                 Source::Memory,
                 FlagValue {
-                    namespace: namespace.to_string(),
+                    package: package.to_string(),
                     name: "test".to_string(),
                     state: FlagState::Disabled,
                     permission: Permission::ReadOnly,
@@ -106,7 +112,7 @@
             )
             .unwrap();
         let cache = builder.build();
-        let expect_content = r#"package aconfig.example;
+        let expect_content = r#"package com.example;
 
         import android.provider.DeviceConfig;
 
@@ -118,8 +124,8 @@
 
             public static boolean test2() {
                 return DeviceConfig.getBoolean(
-                    "example",
-                    "test2__test2",
+                    "ns",
+                    "com.example.test2",
                     false
                 );
             }
@@ -127,10 +133,13 @@
         }
         "#;
         let file = generate_java_code(&cache).unwrap();
-        assert_eq!("aconfig/example/Flags.java", file.path.to_str().unwrap());
+        assert_eq!("com/example/Flags.java", file.path.to_str().unwrap());
         assert_eq!(
-            expect_content.replace(' ', ""),
-            String::from_utf8(file.contents).unwrap().replace(' ', "")
+            None,
+            crate::test::first_significant_code_diff(
+                expect_content,
+                &String::from_utf8(file.contents).unwrap()
+            )
         );
     }
 }
diff --git a/tools/aconfig/src/codegen_rust.rs b/tools/aconfig/src/codegen_rust.rs
index a48e464..98caeae 100644
--- a/tools/aconfig/src/codegen_rust.rs
+++ b/tools/aconfig/src/codegen_rust.rs
@@ -20,13 +20,18 @@
 
 use crate::aconfig::{FlagState, Permission};
 use crate::cache::{Cache, Item};
+use crate::codegen;
 use crate::commands::OutputFile;
 
 pub fn generate_rust_code(cache: &Cache) -> Result<OutputFile> {
-    let namespace = cache.namespace();
+    let package = cache.package();
     let parsed_flags: Vec<TemplateParsedFlag> =
-        cache.iter().map(|item| create_template_parsed_flag(namespace, item)).collect();
-    let context = TemplateContext { namespace: namespace.to_string(), parsed_flags };
+        cache.iter().map(|item| TemplateParsedFlag::new(package, item)).collect();
+    let context = TemplateContext {
+        package: package.to_string(),
+        parsed_flags,
+        modules: package.split('.').map(|s| s.to_string()).collect::<Vec<_>>(),
+    };
     let mut template = TinyTemplate::new();
     template.add_template("rust_code_gen", include_str!("../templates/rust.template"))?;
     let contents = template.render("rust_code_gen", &context)?;
@@ -36,14 +41,16 @@
 
 #[derive(Serialize)]
 struct TemplateContext {
-    pub namespace: String,
+    pub package: String,
     pub parsed_flags: Vec<TemplateParsedFlag>,
+    pub modules: Vec<String>,
 }
 
 #[derive(Serialize)]
 struct TemplateParsedFlag {
     pub name: String,
-    pub fn_name: String,
+    pub device_config_namespace: String,
+    pub device_config_flag: String,
 
     // TinyTemplate's conditionals are limited to single <bool> expressions; list all options here
     // Invariant: exactly one of these fields will be true
@@ -52,28 +59,32 @@
     pub is_read_write: bool,
 }
 
-#[allow(clippy::nonminimal_bool)]
-fn create_template_parsed_flag(namespace: &str, item: &Item) -> TemplateParsedFlag {
-    let template = TemplateParsedFlag {
-        name: item.name.clone(),
-        fn_name: format!("{}_{}", namespace, &item.name),
-        is_read_only_enabled: item.permission == Permission::ReadOnly
-            && item.state == FlagState::Enabled,
-        is_read_only_disabled: item.permission == Permission::ReadOnly
-            && item.state == FlagState::Disabled,
-        is_read_write: item.permission == Permission::ReadWrite,
-    };
-    #[rustfmt::skip]
-    debug_assert!(
-        (template.is_read_only_enabled && !template.is_read_only_disabled && !template.is_read_write) ||
-        (!template.is_read_only_enabled && template.is_read_only_disabled && !template.is_read_write) ||
-        (!template.is_read_only_enabled && !template.is_read_only_disabled && template.is_read_write),
-        "TemplateParsedFlag invariant failed: {} {} {}",
-        template.is_read_only_enabled,
-        template.is_read_only_disabled,
-        template.is_read_write,
-    );
-    template
+impl TemplateParsedFlag {
+    #[allow(clippy::nonminimal_bool)]
+    fn new(package: &str, item: &Item) -> Self {
+        let template = TemplateParsedFlag {
+            name: item.name.clone(),
+            device_config_namespace: item.namespace.to_string(),
+            device_config_flag: codegen::create_device_config_ident(package, &item.name)
+                .expect("values checked at cache creation time"),
+            is_read_only_enabled: item.permission == Permission::ReadOnly
+                && item.state == FlagState::Enabled,
+            is_read_only_disabled: item.permission == Permission::ReadOnly
+                && item.state == FlagState::Disabled,
+            is_read_write: item.permission == Permission::ReadWrite,
+        };
+        #[rustfmt::skip]
+        debug_assert!(
+            (template.is_read_only_enabled && !template.is_read_only_disabled && !template.is_read_write) ||
+            (!template.is_read_only_enabled && template.is_read_only_disabled && !template.is_read_write) ||
+            (!template.is_read_only_enabled && !template.is_read_only_disabled && template.is_read_write),
+            "TemplateParsedFlag invariant failed: {} {} {}",
+            template.is_read_only_enabled,
+            template.is_read_only_disabled,
+            template.is_read_write,
+        );
+        template
+    }
 }
 
 #[cfg(test)]
@@ -86,26 +97,41 @@
         let generated = generate_rust_code(&cache).unwrap();
         assert_eq!("src/lib.rs", format!("{}", generated.path.display()));
         let expected = r#"
+pub mod com {
+pub mod android {
+pub mod aconfig {
+pub mod test {
 #[inline(always)]
-pub const fn r#test_disabled_ro() -> bool {
+pub const fn r#disabled_ro() -> bool {
     false
 }
 
 #[inline(always)]
-pub fn r#test_disabled_rw() -> bool {
-    flags_rust::GetServerConfigurableFlag("test", "disabled_rw", "false") == "true"
+pub fn r#disabled_rw() -> bool {
+    flags_rust::GetServerConfigurableFlag("aconfig_test", "com.android.aconfig.test.disabled_rw", "false") == "true"
 }
 
 #[inline(always)]
-pub const fn r#test_enabled_ro() -> bool {
+pub const fn r#enabled_ro() -> bool {
     true
 }
 
 #[inline(always)]
-pub fn r#test_enabled_rw() -> bool {
-    flags_rust::GetServerConfigurableFlag("test", "enabled_rw", "false") == "true"
+pub fn r#enabled_rw() -> bool {
+    flags_rust::GetServerConfigurableFlag("aconfig_test", "com.android.aconfig.test.enabled_rw", "false") == "true"
+}
+
+}
+}
+}
 }
 "#;
-        assert_eq!(expected.trim(), String::from_utf8(generated.contents).unwrap().trim());
+        assert_eq!(
+            None,
+            crate::test::first_significant_code_diff(
+                expected,
+                &String::from_utf8(generated.contents).unwrap()
+            )
+        );
     }
 }
diff --git a/tools/aconfig/src/commands.rs b/tools/aconfig/src/commands.rs
index 3ae72c6..586ba04 100644
--- a/tools/aconfig/src/commands.rs
+++ b/tools/aconfig/src/commands.rs
@@ -55,12 +55,8 @@
     pub contents: Vec<u8>,
 }
 
-pub fn create_cache(
-    namespace: &str,
-    declarations: Vec<Input>,
-    values: Vec<Input>,
-) -> Result<Cache> {
-    let mut builder = CacheBuilder::new(namespace.to_owned())?;
+pub fn create_cache(package: &str, declarations: Vec<Input>, values: Vec<Input>) -> Result<Cache> {
+    let mut builder = CacheBuilder::new(package.to_owned())?;
 
     for mut input in declarations {
         let mut contents = String::new();
@@ -68,11 +64,11 @@
         let dec_list = FlagDeclarations::try_from_text_proto(&contents)
             .with_context(|| format!("Failed to parse {}", input.source))?;
         ensure!(
-            namespace == dec_list.namespace,
-            "Failed to parse {}: expected namespace {}, got {}",
+            package == dec_list.package,
+            "Failed to parse {}: expected package {}, got {}",
             input.source,
-            namespace,
-            dec_list.namespace
+            package,
+            dec_list.package
         );
         for d in dec_list.flags.into_iter() {
             builder.add_flag_declaration(input.source.clone(), d)?;
@@ -110,8 +106,9 @@
     for item in sort_and_iter_items(caches).filter(|item| item.permission == Permission::ReadWrite)
     {
         let line = format!(
-            "{}/{}:{}\n",
+            "{}:{}.{}={}\n",
             item.namespace,
+            item.package,
             item.name,
             match item.state {
                 FlagState::Enabled => "enabled",
@@ -129,7 +126,7 @@
     {
         let line = format!(
             "persist.device_config.{}.{}={}\n",
-            item.namespace,
+            item.package,
             item.name,
             match item.state {
                 FlagState::Enabled => "true",
@@ -155,7 +152,7 @@
             for item in sort_and_iter_items(caches) {
                 let line = format!(
                     "{}/{}: {:?} {:?}\n",
-                    item.namespace, item.name, item.state, item.permission
+                    item.package, item.name, item.state, item.permission
                 );
                 output.extend_from_slice(line.as_bytes());
             }
@@ -181,7 +178,7 @@
 }
 
 fn sort_and_iter_caches(mut caches: Vec<Cache>) -> impl Iterator<Item = Cache> {
-    caches.sort_by_cached_key(|cache| cache.namespace().to_string());
+    caches.sort_by_cached_key(|cache| cache.package().to_string());
     caches.into_iter()
 }
 
@@ -190,55 +187,58 @@
     use super::*;
     use crate::aconfig::{FlagState, Permission};
 
-    fn create_test_cache_ns1() -> Cache {
+    fn create_test_cache_com_example() -> Cache {
         let s = r#"
-        namespace: "ns1"
+        package: "com.example"
         flag {
             name: "a"
+            namespace: "ns"
             description: "Description of a"
         }
         flag {
             name: "b"
+            namespace: "ns"
             description: "Description of b"
         }
         "#;
         let declarations = vec![Input { source: Source::Memory, reader: Box::new(s.as_bytes()) }];
         let o = r#"
         flag_value {
-            namespace: "ns1"
+            package: "com.example"
             name: "a"
             state: DISABLED
             permission: READ_ONLY
         }
         "#;
         let values = vec![Input { source: Source::Memory, reader: Box::new(o.as_bytes()) }];
-        create_cache("ns1", declarations, values).unwrap()
+        create_cache("com.example", declarations, values).unwrap()
     }
 
-    fn create_test_cache_ns2() -> Cache {
+    fn create_test_cache_com_other() -> Cache {
         let s = r#"
-        namespace: "ns2"
+        package: "com.other"
         flag {
             name: "c"
+            namespace: "ns"
             description: "Description of c"
         }
         "#;
         let declarations = vec![Input { source: Source::Memory, reader: Box::new(s.as_bytes()) }];
         let o = r#"
         flag_value {
-            namespace: "ns2"
+            package: "com.other"
             name: "c"
             state: DISABLED
             permission: READ_ONLY
         }
         "#;
         let values = vec![Input { source: Source::Memory, reader: Box::new(o.as_bytes()) }];
-        create_cache("ns2", declarations, values).unwrap()
+        create_cache("com.other", declarations, values).unwrap()
     }
 
     #[test]
     fn test_create_cache() {
-        let caches = create_test_cache_ns1(); // calls create_cache
+        let caches = create_test_cache_com_example(); // calls create_cache
         let item = caches.iter().find(|&item| item.name == "a").unwrap();
         assert_eq!(FlagState::Disabled, item.state);
         assert_eq!(Permission::ReadOnly, item.permission);
@@ -249,7 +249,7 @@
         let caches = vec![crate::test::create_cache()];
         let bytes = create_device_config_defaults(caches).unwrap();
         let text = std::str::from_utf8(&bytes).unwrap();
-        assert_eq!("test/disabled_rw:disabled\ntest/enabled_rw:enabled\n", text);
+        assert_eq!("aconfig_test:com.android.aconfig.test.disabled_rw=disabled\naconfig_test:com.android.aconfig.test.enabled_rw=enabled\n", text);
     }
 
     #[test]
@@ -257,12 +257,12 @@
         let caches = vec![crate::test::create_cache()];
         let bytes = create_device_config_sysprops(caches).unwrap();
         let text = std::str::from_utf8(&bytes).unwrap();
-        assert_eq!("persist.device_config.test.disabled_rw=false\npersist.device_config.test.enabled_rw=true\n", text);
+        assert_eq!("persist.device_config.com.android.aconfig.test.disabled_rw=false\npersist.device_config.com.android.aconfig.test.enabled_rw=true\n", text);
     }
 
     #[test]
     fn test_dump_text_format() {
-        let caches = vec![create_test_cache_ns1()];
+        let caches = vec![create_test_cache_com_example()];
         let bytes = dump_cache(caches, DumpFormat::Text).unwrap();
         let text = std::str::from_utf8(&bytes).unwrap();
         assert!(text.contains("a: Disabled"));
@@ -273,7 +273,7 @@
         use crate::protos::{ProtoFlagPermission, ProtoFlagState, ProtoTracepoint};
         use protobuf::Message;
 
-        let caches = vec![create_test_cache_ns1()];
+        let caches = vec![create_test_cache_com_example()];
         let bytes = dump_cache(caches, DumpFormat::Protobuf).unwrap();
         let actual = ProtoParsedFlags::parse_from_bytes(&bytes).unwrap();
 
@@ -284,7 +284,7 @@
 
         let item =
             actual.parsed_flag.iter().find(|item| item.name == Some("b".to_string())).unwrap();
-        assert_eq!(item.namespace(), "ns1");
+        assert_eq!(item.package(), "com.example");
         assert_eq!(item.name(), "b");
         assert_eq!(item.description(), "Description of b");
         assert_eq!(item.state(), ProtoFlagState::DISABLED);
@@ -298,18 +298,22 @@
 
     #[test]
     fn test_dump_multiple_caches() {
-        let caches = vec![create_test_cache_ns1(), create_test_cache_ns2()];
+        let caches = vec![create_test_cache_com_example(), create_test_cache_com_other()];
         let bytes = dump_cache(caches, DumpFormat::Protobuf).unwrap();
         let dump = ProtoParsedFlags::parse_from_bytes(&bytes).unwrap();
         assert_eq!(
             dump.parsed_flag
                 .iter()
-                .map(|parsed_flag| format!("{}/{}", parsed_flag.namespace(), parsed_flag.name()))
+                .map(|parsed_flag| format!("{}/{}", parsed_flag.package(), parsed_flag.name()))
                 .collect::<Vec<_>>(),
-            vec!["ns1/a".to_string(), "ns1/b".to_string(), "ns2/c".to_string()]
+            vec![
+                "com.example/a".to_string(),
+                "com.example/b".to_string(),
+                "com.other/c".to_string()
+            ]
         );
 
-        let caches = vec![create_test_cache_ns2(), create_test_cache_ns1()];
+        let caches = vec![create_test_cache_com_other(), create_test_cache_com_example()];
         let bytes = dump_cache(caches, DumpFormat::Protobuf).unwrap();
         let dump_reversed_input = ProtoParsedFlags::parse_from_bytes(&bytes).unwrap();
         assert_eq!(dump, dump_reversed_input);
diff --git a/tools/aconfig/src/main.rs b/tools/aconfig/src/main.rs
index dab0191..5a820d9 100644
--- a/tools/aconfig/src/main.rs
+++ b/tools/aconfig/src/main.rs
@@ -44,7 +44,7 @@
         .subcommand_required(true)
         .subcommand(
             Command::new("create-cache")
-                .arg(Arg::new("namespace").long("namespace").required(true))
+                .arg(Arg::new("package").long("package").required(true))
                 .arg(Arg::new("declarations").long("declarations").action(ArgAction::Append))
                 .arg(Arg::new("values").long("values").action(ArgAction::Append))
                 .arg(Arg::new("cache").long("cache").required(true)),
@@ -134,10 +134,10 @@
     let matches = cli().get_matches();
     match matches.subcommand() {
         Some(("create-cache", sub_matches)) => {
-            let namespace = get_required_arg::<String>(sub_matches, "namespace")?;
+            let package = get_required_arg::<String>(sub_matches, "package")?;
             let declarations = open_zero_or_more_files(sub_matches, "declarations")?;
             let values = open_zero_or_more_files(sub_matches, "values")?;
-            let cache = commands::create_cache(namespace, declarations, values)?;
+            let cache = commands::create_cache(package, declarations, values)?;
             let path = get_required_arg::<String>(sub_matches, "cache")?;
             let file = fs::File::create(path)?;
             cache.write_to_writer(file)?;
diff --git a/tools/aconfig/src/test.rs b/tools/aconfig/src/test.rs
index 621381a..cc19c6a 100644
--- a/tools/aconfig/src/test.rs
+++ b/tools/aconfig/src/test.rs
@@ -18,10 +18,11 @@
 pub mod test_utils {
     use crate::cache::Cache;
     use crate::commands::{Input, Source};
+    use itertools;
 
     pub fn create_cache() -> Cache {
         crate::commands::create_cache(
-            "test",
+            "com.android.aconfig.test",
             vec![Input {
                 source: Source::File("testdata/test.aconfig".to_string()),
                 reader: Box::new(include_bytes!("../testdata/test.aconfig").as_slice()),
@@ -39,6 +40,54 @@
         )
         .unwrap()
     }
+
+    pub fn first_significant_code_diff(a: &str, b: &str) -> Option<String> {
+        let a = a.lines().map(|line| line.trim_start()).filter(|line| !line.is_empty());
+        let b = b.lines().map(|line| line.trim_start()).filter(|line| !line.is_empty());
+        match itertools::diff_with(a, b, |left, right| left == right) {
+            Some(itertools::Diff::FirstMismatch(_, mut left, mut right)) => {
+                Some(format!("'{}' vs '{}'", left.next().unwrap(), right.next().unwrap()))
+            }
+            Some(itertools::Diff::Shorter(_, mut left)) => {
+                Some(format!("LHS trailing data: '{}'", left.next().unwrap()))
+            }
+            Some(itertools::Diff::Longer(_, mut right)) => {
+                Some(format!("RHS trailing data: '{}'", right.next().unwrap()))
+            }
+            None => None,
+        }
+    }
+
+    #[test]
+    fn test_first_significant_code_diff() {
+        assert!(first_significant_code_diff("", "").is_none());
+        assert!(first_significant_code_diff("   a", "\n\na\n").is_none());
+        let a = r#"
+        public class A {
+            private static final String FOO = "FOO";
+            public static void main(String[] args) {
+                System.out.println("FOO=" + FOO);
+            }
+        }
+        "#;
+        let b = r#"
+        public class A {
+            private static final String FOO = "BAR";
+            public static void main(String[] args) {
+                System.out.println("foo=" + FOO);
+            }
+        }
+        "#;
+        assert_eq!(Some(r#"'private static final String FOO = "FOO";' vs 'private static final String FOO = "BAR";'"#.to_string()), first_significant_code_diff(a, b));
+        assert_eq!(
+            Some("LHS trailing data: 'b'".to_string()),
+            first_significant_code_diff("a\nb", "a")
+        );
+        assert_eq!(
+            Some("RHS trailing data: 'b'".to_string()),
+            first_significant_code_diff("a", "a\nb")
+        );
+    }
 }
 
 #[cfg(test)]
diff --git a/tools/aconfig/templates/cpp.template b/tools/aconfig/templates/cpp.template
index ae8b59f..93f9b80 100644
--- a/tools/aconfig/templates/cpp.template
+++ b/tools/aconfig/templates/cpp.template
@@ -1,19 +1,18 @@
-#ifndef {namespace}_HEADER_H
-#define {namespace}_HEADER_H
-#include "{namespace}.h"
+#ifndef {header}_HEADER_H
+#define {header}_HEADER_H
 {{ if readwrite }}
 #include <server_configurable_flags/get_flags.h>
 using namespace server_configurable_flags;
 {{ endif }}
-namespace {namespace} \{
+namespace {cpp_namespace} \{
     {{ for item in class_elements}}
     class {item.flag_name} \{
         public:
             virtual const bool value() \{
                 {{ if item.readwrite- }}
                 return GetServerConfigurableFlag(
-                    "{namespace}",
-                    "{item.flag_name}",
+                    "{item.device_config_namespace}",
+                    "{item.device_config_flag}",
                     "{item.default_value}") == "true";
                 {{ -else- }}
                 return {item.default_value};
diff --git a/tools/aconfig/templates/java.template b/tools/aconfig/templates/java.template
index 30c7ad7..a3d3319 100644
--- a/tools/aconfig/templates/java.template
+++ b/tools/aconfig/templates/java.template
@@ -1,4 +1,4 @@
-package aconfig.{namespace};
+package {package};
 {{ if readwrite }}
 import android.provider.DeviceConfig;
 {{ endif }}
@@ -7,8 +7,8 @@
     public static boolean {item.method_name}() \{
         {{ if item.readwrite- }}
         return DeviceConfig.getBoolean(
-            "{namespace}",
-            "{item.feature_name}__{item.flag_name}",
+            "{item.device_config_namespace}",
+            "{item.device_config_flag}",
             {item.default_value}
         );
         {{ -else- }}
diff --git a/tools/aconfig/templates/rust.template b/tools/aconfig/templates/rust.template
index d7f4e8d..d914943 100644
--- a/tools/aconfig/templates/rust.template
+++ b/tools/aconfig/templates/rust.template
@@ -1,23 +1,29 @@
+{{- for mod in modules -}}
+pub mod {mod} \{
+{{ endfor -}}
 {{- for parsed_flag in parsed_flags -}}
 {{- if parsed_flag.is_read_only_disabled -}}
 #[inline(always)]
-pub const fn r#{parsed_flag.fn_name}() -> bool \{
+pub const fn r#{parsed_flag.name}() -> bool \{
     false
 }
 
 {{ endif -}}
 {{- if parsed_flag.is_read_only_enabled -}}
 #[inline(always)]
-pub const fn r#{parsed_flag.fn_name}() -> bool \{
+pub const fn r#{parsed_flag.name}() -> bool \{
     true
 }
 
 {{ endif -}}
 {{- if parsed_flag.is_read_write -}}
 #[inline(always)]
-pub fn r#{parsed_flag.fn_name}() -> bool \{
-    flags_rust::GetServerConfigurableFlag("{namespace}", "{parsed_flag.name}", "false") == "true"
+pub fn r#{parsed_flag.name}() -> bool \{
+    flags_rust::GetServerConfigurableFlag("{parsed_flag.device_config_namespace}", "{parsed_flag.device_config_flag}", "false") == "true"
 }
 
 {{ endif -}}
 {{- endfor -}}
+{{- for mod in modules -}}
+}
+{{ endfor -}}
diff --git a/tools/aconfig/testdata/first.values b/tools/aconfig/testdata/first.values
index 3c49111..e524404 100644
--- a/tools/aconfig/testdata/first.values
+++ b/tools/aconfig/testdata/first.values
@@ -1,17 +1,17 @@
 flag_value {
-    namespace: "test"
+    package: "com.android.aconfig.test"
     name: "disabled_ro"
     state: DISABLED
     permission: READ_ONLY
 }
 flag_value {
-    namespace: "test"
+    package: "com.android.aconfig.test"
     name: "enabled_ro"
     state: DISABLED
     permission: READ_WRITE
 }
 flag_value {
-    namespace: "test"
+    package: "com.android.aconfig.test"
     name: "enabled_rw"
     state: ENABLED
     permission: READ_WRITE
diff --git a/tools/aconfig/testdata/second.values b/tools/aconfig/testdata/second.values
index 3fe11ab..aa09cf6 100644
--- a/tools/aconfig/testdata/second.values
+++ b/tools/aconfig/testdata/second.values
@@ -1,5 +1,5 @@
 flag_value {
-    namespace: "test"
+    package: "com.android.aconfig.test"
     name: "enabled_ro"
     state: ENABLED
     permission: READ_ONLY
diff --git a/tools/aconfig/testdata/test.aconfig b/tools/aconfig/testdata/test.aconfig
index 986a526..d09396a 100644
--- a/tools/aconfig/testdata/test.aconfig
+++ b/tools/aconfig/testdata/test.aconfig
@@ -1,10 +1,11 @@
-namespace: "test"
+package: "com.android.aconfig.test"
 
 # This flag's final value is calculated from:
 # - test.aconfig: DISABLED + READ_WRITE (default)
 # - first.values: DISABLED + READ_ONLY
 flag {
     name: "disabled_ro"
+    namespace: "aconfig_test"
     description: "This flag is DISABLED + READ_ONLY"
 }
 
@@ -12,6 +13,7 @@
 # - test.aconfig: DISABLED + READ_WRITE (default)
 flag {
     name: "disabled_rw"
+    namespace: "aconfig_test"
     description: "This flag is DISABLED + READ_WRITE"
 }
 
@@ -21,6 +23,7 @@
 # - second.values: ENABLED + READ_ONLY
 flag {
     name: "enabled_ro"
+    namespace: "aconfig_test"
     description: "This flag is ENABLED + READ_ONLY"
 }
 
@@ -29,5 +32,6 @@
 # - first.values: ENABLED + READ_WRITE
 flag {
     name: "enabled_rw"
+    namespace: "aconfig_test"
     description: "This flag is ENABLED + READ_WRITE"
 }