diff --git a/binding/java/src/main/java/org/lionsoul/ip2region/service/Config.java b/binding/java/src/main/java/org/lionsoul/ip2region/service/Config.java
index c6f1832..0cb938c 100644
--- a/binding/java/src/main/java/org/lionsoul/ip2region/service/Config.java
+++ b/binding/java/src/main/java/org/lionsoul/ip2region/service/Config.java
@@ -23,7 +23,7 @@ public class Config {
     public static final int VIndexCache = 1;
     public static final int BufferCache = 2;
 
-    // alias of BufferCache but easier to understand
+    // alias of BufferCache but easier to understand or Remember
     public static final int FullCache = 2;
 
     // search cache policy
diff --git a/binding/java/src/test/java/org/lionsoul/ip2region/service/ConfigTest.java b/binding/java/src/test/java/org/lionsoul/ip2region/service/ConfigTest.java
index c716139..ef26581 100644
--- a/binding/java/src/test/java/org/lionsoul/ip2region/service/ConfigTest.java
+++ b/binding/java/src/test/java/org/lionsoul/ip2region/service/ConfigTest.java
@@ -1,4 +1,6 @@
 package org.lionsoul.ip2region.service;
+import java.io.File;
+import java.io.FileInputStream;
 import java.io.IOException;
 import java.security.CodeSource;
 
@@ -23,13 +25,35 @@ public class ConfigTest {
     @Test
     public void testBuildV4Config() throws IOException, XdbException, InvalidConfigException {
         final Config v4Config = Config.custom()
-            .setCachePolicy(Config.BufferCache)
+            .setCachePolicy(Config.VIndexCache)
             .setXdbPath(getDataPath("ip2region_v4.xdb"))
             .setSearchers(20)
             .asV4();
         log.debugf("builded config: %s", v4Config);
     }
 
+    @Test
+    public void testBuildV4ConfigFromFile() throws IOException, XdbException, InvalidConfigException {
+        final Config v4Config = Config.custom()
+            .setCachePolicy(Config.BufferCache)
+            .setXdbFile(new File(getDataPath("ip2region_v4.xdb")))
+            .setSearchers(20)
+            .asV4();
+        log.debugf("builded config: %s", v4Config);
+    }
+
+    @Test
+    public void testBuildV4ConfigFromInputStream() throws IOException, XdbException, InvalidConfigException {
+        final Config v4Config = Config.custom()
+            .setCachePolicy(Config.BufferCache)
+            .setXdbInputStream(new FileInputStream(getDataPath("ip2region_v4.xdb")))
+            .setSearchers(20)
+            .asV4();
+        log.debugf("builded config: %s", v4Config);
+    }
+
+    // --- IPv6
+
     @Test
     public void testBuildV6Config() throws IOException, XdbException, InvalidConfigException {
         final Config v4Config = Config.custom()
@@ -39,4 +63,25 @@ public class ConfigTest {
             .asV6();
         log.debugf("builded config: %s", v4Config);
     }
+
+    @Test
+    public void testBuildV6ConfigFromFile() throws IOException, XdbException, InvalidConfigException {
+        final Config v4Config = Config.custom()
+            .setCachePolicy(Config.BufferCache)
+            .setXdbFile(new File(getDataPath("ip2region_v6.xdb")))
+            .setSearchers(20)
+            .asV6();
+        log.debugf("builded config: %s", v4Config);
+    }
+
+    @Test
+    public void testBuildV6ConfigFromInputStream() throws IOException, XdbException, InvalidConfigException {
+        final Config v4Config = Config.custom()
+            .setCachePolicy(Config.BufferCache)
+            .setXdbInputStream(new FileInputStream(getDataPath("ip2region_v6.xdb")))
+            .setSearchers(20)
+            .asV6();
+        log.debugf("builded config: %s", v4Config);
+    }
+
 }