diff --git a/tools/aconfig/aconfig_storage_file/srcs/android/aconfig/storage/ByteBufferReader.java b/tools/aconfig/aconfig_storage_file/srcs/android/aconfig/storage/ByteBufferReader.java
index 1c72364..4bea083 100644
--- a/tools/aconfig/aconfig_storage_file/srcs/android/aconfig/storage/ByteBufferReader.java
+++ b/tools/aconfig/aconfig_storage_file/srcs/android/aconfig/storage/ByteBufferReader.java
@@ -48,6 +48,10 @@
         return new String(bytes, StandardCharsets.UTF_8);
     }
 
+    public int readByte(int i) {
+        return Byte.toUnsignedInt(mByteBuffer.get(i));
+    }
+
     public void position(int newPosition) {
         mByteBuffer.position(newPosition);
     }
diff --git a/tools/aconfig/aconfig_storage_file/srcs/android/aconfig/storage/FlagValueList.java b/tools/aconfig/aconfig_storage_file/srcs/android/aconfig/storage/FlagValueList.java
index 0ddc147..493436d 100644
--- a/tools/aconfig/aconfig_storage_file/srcs/android/aconfig/storage/FlagValueList.java
+++ b/tools/aconfig/aconfig_storage_file/srcs/android/aconfig/storage/FlagValueList.java
@@ -17,33 +17,21 @@
 package android.aconfig.storage;
 
 import java.nio.ByteBuffer;
-import java.util.ArrayList;
-import java.util.List;
 
 public class FlagValueList {
 
     private Header mHeader;
-    private List<Boolean> mList;
-
-    private int mSize;
+    private ByteBufferReader mReader;
 
     public static FlagValueList fromBytes(ByteBuffer bytes) {
         FlagValueList flagValueList = new FlagValueList();
-        ByteBufferReader reader = new ByteBufferReader(bytes);
-        Header header = Header.fromBytes(reader);
-        flagValueList.mHeader = header;
-        flagValueList.mList = new ArrayList(header.mNumFlags);
-        reader.position(header.mBooleanValueOffset);
-        for (int i = 0; i < header.mNumFlags; i++) {
-            boolean val = reader.readByte() == 1;
-            flagValueList.mList.add(val);
-        }
-        flagValueList.mSize = flagValueList.mList.size();
+        flagValueList.mReader = new ByteBufferReader(bytes);
+        flagValueList.mHeader = Header.fromBytes(flagValueList.mReader);
         return flagValueList;
     }
 
-    public boolean get(int index) {
-        return mList.get(index);
+    public boolean getBoolean(int index) {
+        return mReader.readByte(mHeader.mBooleanValueOffset + index) == 1;
     }
 
     public Header getHeader() {
@@ -51,7 +39,7 @@
     }
 
     public int size() {
-        return mSize;
+        return mHeader.mNumFlags;
     }
 
     public static class Header {
diff --git a/tools/aconfig/aconfig_storage_file/srcs/android/aconfig/storage/PackageTable.java b/tools/aconfig/aconfig_storage_file/srcs/android/aconfig/storage/PackageTable.java
index d04e1ac..7ef947d 100644
--- a/tools/aconfig/aconfig_storage_file/srcs/android/aconfig/storage/PackageTable.java
+++ b/tools/aconfig/aconfig_storage_file/srcs/android/aconfig/storage/PackageTable.java
@@ -17,31 +17,30 @@
 package android.aconfig.storage;
 
 import java.nio.ByteBuffer;
-import java.util.HashMap;
-import java.util.Map;
 import java.util.Objects;
 
 public class PackageTable {
 
     private Header mHeader;
-    private Map<String, Node> mNodeMap;
+    private ByteBufferReader mReader;
 
     public static PackageTable fromBytes(ByteBuffer bytes) {
         PackageTable packageTable = new PackageTable();
-        ByteBufferReader reader = new ByteBufferReader(bytes);
-        Header header = Header.fromBytes(reader);
-        packageTable.mHeader = header;
-        packageTable.mNodeMap = new HashMap(TableUtils.getTableSize(header.mNumPackages));
-        reader.position(header.mNodeOffset);
-        for (int i = 0; i < header.mNumPackages; i++) {
-            Node node = Node.fromBytes(reader);
-            packageTable.mNodeMap.put(node.mPackageName, node);
-        }
+        packageTable.mReader = new ByteBufferReader(bytes);
+        packageTable.mHeader = Header.fromBytes(packageTable.mReader);
+
         return packageTable;
     }
 
     public Node get(String packageName) {
-        return mNodeMap.get(packageName);
+        mReader.position(mHeader.mNodeOffset);
+        for (int i = 0; i < mHeader.mNumPackages; i++) {
+            Node node = Node.fromBytes(mReader);
+            if (Objects.equals(node.mPackageName, packageName)) {
+                return node;
+            }
+        }
+        throw new AconfigStorageException("get cannot find package: " + packageName);
     }
 
     public Header getHeader() {
diff --git a/tools/aconfig/aconfig_storage_file/tests/srcs/FlagValueListTest.java b/tools/aconfig/aconfig_storage_file/tests/srcs/FlagValueListTest.java
index c18590a..1b0de63 100644
--- a/tools/aconfig/aconfig_storage_file/tests/srcs/FlagValueListTest.java
+++ b/tools/aconfig/aconfig_storage_file/tests/srcs/FlagValueListTest.java
@@ -53,7 +53,7 @@
         assertEquals(expected.length, flagValueList.size());
 
         for (int i = 0; i < flagValueList.size(); i++) {
-            assertEquals(expected[i], flagValueList.get(i));
+            assertEquals(expected[i], flagValueList.getBoolean(i));
         }
     }
 
@@ -68,10 +68,10 @@
 
         PackageTable.Node pNode = packageTable.get("com.android.aconfig.storage.test_1");
         FlagTable.Node fNode = flagTable.get(pNode.getPackageId(), "enabled_rw");
-        assertTrue(flagValueList.get(pNode.getBooleanStartIndex() + fNode.getFlagIndex()));
+        assertTrue(flagValueList.getBoolean(pNode.getBooleanStartIndex() + fNode.getFlagIndex()));
 
         pNode = packageTable.get("com.android.aconfig.storage.test_4");
         fNode = flagTable.get(pNode.getPackageId(), "enabled_fixed_ro");
-        assertTrue(flagValueList.get(pNode.getBooleanStartIndex() + fNode.getFlagIndex()));
+        assertTrue(flagValueList.getBoolean(pNode.getBooleanStartIndex() + fNode.getFlagIndex()));
     }
 }
diff --git a/tools/aconfig/aconfig_storage_read_api/srcs/android/aconfig/storage/StorageInternalReader.java b/tools/aconfig/aconfig_storage_read_api/srcs/android/aconfig/storage/StorageInternalReader.java
index 71c1c0d..29ebee5 100644
--- a/tools/aconfig/aconfig_storage_read_api/srcs/android/aconfig/storage/StorageInternalReader.java
+++ b/tools/aconfig/aconfig_storage_read_api/srcs/android/aconfig/storage/StorageInternalReader.java
@@ -56,7 +56,7 @@
         if (index >= mFlagValueList.size()) {
             throw new AconfigStorageException("Fail to get boolean flag value");
         }
-        return mFlagValueList.get(index);
+        return mFlagValueList.getBoolean(index);
     }
 
     private int getPackageBooleanStartOffset(String packageName) {