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 c916980..c6f1832 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
@@ -23,6 +23,9 @@ public class Config {
     public static final int VIndexCache = 1;
     public static final int BufferCache = 2;
 
+    // alias of BufferCache but easier to understand
+    public static final int FullCache = 2;
+
     // search cache policy
     public final int cachePolicy;
     public final Version ipVersion;
diff --git a/binding/java/src/main/java/org/lionsoul/ip2region/xdb/Searcher.java b/binding/java/src/main/java/org/lionsoul/ip2region/xdb/Searcher.java
index 98b8475..a2c3ddf 100644
--- a/binding/java/src/main/java/org/lionsoul/ip2region/xdb/Searcher.java
+++ b/binding/java/src/main/java/org/lionsoul/ip2region/xdb/Searcher.java
@@ -204,13 +204,17 @@ public class Searcher {
         return new Header(buff);
     }
 
-    public static Header loadHeaderFromFile(String dbPath) throws IOException {
-        final RandomAccessFile handle = new RandomAccessFile(dbPath, "r");
+    public static Header loadHeaderFromFile(File xdbFile) throws IOException {
+        final RandomAccessFile handle = new RandomAccessFile(xdbFile, "r");
         final Header header = loadHeader(handle);
         handle.close();
         return header;
     }
 
+    public static Header loadHeaderFromFile(String xdbPath) throws IOException {
+        return loadHeaderFromFile(new File(xdbPath));
+    }
+
     public static byte[] loadVectorIndex(RandomAccessFile handle) throws IOException {
         handle.seek(HeaderInfoLength);
         int len = VectorIndexRows * VectorIndexCols * VectorIndexSize;
@@ -223,13 +227,17 @@ public class Searcher {
         return buff;
     }
 
-    public static byte[] loadVectorIndexFromFile(String dbPath) throws IOException {
-        final RandomAccessFile handle = new RandomAccessFile(dbPath, "r");
+    public static byte[] loadVectorIndexFromFile(File xdbFile) throws IOException {
+        final RandomAccessFile handle = new RandomAccessFile(xdbFile, "r");
         final byte[] vIndex = loadVectorIndex(handle);
         handle.close();
         return vIndex;
     }
 
+    public static byte[] loadVectorIndexFromFile(String xdbPath) throws IOException {
+        return loadVectorIndexFromFile(new File(xdbPath));
+    }
+
     public static LongByteArray loadContent(RandomAccessFile handle) throws IOException {
         handle.seek(0);
         // check the length and do the buff load
@@ -249,13 +257,17 @@ public class Searcher {
         return byteArray;
     }
 
-    public static LongByteArray loadContentFromFile(String dbPath) throws IOException {
-        final RandomAccessFile handle = new RandomAccessFile(dbPath, "r");
+    public static LongByteArray loadContentFromFile(File xdbFile) throws IOException {
+        final RandomAccessFile handle = new RandomAccessFile(xdbFile, "r");
         final LongByteArray content = loadContent(handle);
         handle.close();
         return content;
     }
 
+    public static LongByteArray loadContentFromFile(String xdbPath) throws IOException {
+        return loadContentFromFile(new File(xdbPath));
+    }
+
     // --- verify util function
 
     // Verify if the current Searcher could be used to search the specified xdb file.
diff --git a/binding/java/src/test/java/org/lionsoul/ip2region/service/SearcherPoolTest.java b/binding/java/src/test/java/org/lionsoul/ip2region/service/SearcherPoolTest.java
index 5d07761..5c32f63 100644
--- a/binding/java/src/test/java/org/lionsoul/ip2region/service/SearcherPoolTest.java
+++ b/binding/java/src/test/java/org/lionsoul/ip2region/service/SearcherPoolTest.java
@@ -32,6 +32,30 @@ public class SearcherPoolTest {
         log.debugf("v4 searcher pool closed gracefully");
     }
 
+    @Test
+    public void testInMemV4SearcherPool() throws Exception {
+        final Config v4Config = Config.custom()
+            .setCachePolicy(Config.FullCache)
+            .setSearchers(5)
+            .setXdbPath(ConfigTest.getDataPath("ip2region_v4.xdb"))
+            .asV4();
+
+
+        final String ipStr = "58.250.36.41";
+        final SearcherPool v4Pool = SearcherPool.create(v4Config);
+        for (int i = 0; i < 20; i++) {
+            final Searcher searcher = v4Pool.borrowSearcher();
+            log.debugf("borrowed searcher %d: %s", i, searcher.toString());
+            final String region = searcher.search(ipStr);
+            log.debugf("search(%s)=%s", ipStr, region);
+            v4Pool.returnSearcher(searcher);
+            log.debugf("return searcher %d", i);
+        }
+
+        v4Pool.close();
+        log.debugf("v4 searcher pool closed gracefully");
+    }
+
     @Test
     public void testV6SearcherPool() throws Exception {
         final Config v6Config = Config.custom()