diff --git a/tools/aconfig/templates/FakeFeatureFlagsImpl.java.template b/tools/aconfig/templates/FakeFeatureFlagsImpl.java.template
new file mode 100644
index 0000000..db35d28
--- /dev/null
+++ b/tools/aconfig/templates/FakeFeatureFlagsImpl.java.template
@@ -0,0 +1,59 @@
+package {package_name};
+{{ if is_test_mode }}
+import static java.util.stream.Collectors.toMap;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Stream;
+
+public class FakeFeatureFlagsImpl implements FeatureFlags \{
+{{ for item in class_elements}}
+    @Override
+    public boolean {item.method_name}() \{
+        return getFlag(Flags.FLAG_{item.flag_name_constant_suffix});
+    }
+{{ endfor}}
+    public void setFlag(String flagName, boolean value) \{
+        if (!this.mFlagMap.containsKey(flagName)) \{
+            throw new IllegalArgumentException("no such flag" + flagName);
+        }
+        this.mFlagMap.put(flagName, value);
+    }
+
+    public void resetAll() \{
+        for (Map.Entry entry : mFlagMap.entrySet()) \{
+            entry.setValue(null);
+        }
+    }
+
+    private boolean getFlag(String flagName) \{
+        Boolean value = this.mFlagMap.get(flagName);
+        if (value == null) \{
+            throw new IllegalArgumentException(flagName + " is not set");
+        }
+        return value;
+    }
+
+    private HashMap<String, Boolean> mFlagMap = Stream.of(
+            {{-for item in class_elements}}
+            Flags.FLAG_{item.flag_name_constant_suffix}{{ if not @last }},{{ endif }}
+            {{ -endfor }}
+        )
+        .collect(
+            HashMap::new,
+            (map, elem) -> map.put(elem, null),
+            HashMap::putAll
+        );
+}
+{{ else }}
+{#- Generate only stub if in prod mode #}
+public class FakeFeatureFlagsImpl implements FeatureFlags \{
+{{ for item in class_elements}}
+    @Override
+    public boolean {item.method_name}() \{
+        throw new UnsupportedOperationException(
+            "Method is not implemented.");
+    }
+{{ endfor}}
+}
+{{ endif }}