diff --git a/maker/java/src/main/java/org/lionsoul/ip2region/xdb/Segment.java b/maker/java/src/main/java/org/lionsoul/ip2region/xdb/Segment.java
index 9c6db14..64cb8c6 100644
--- a/maker/java/src/main/java/org/lionsoul/ip2region/xdb/Segment.java
+++ b/maker/java/src/main/java/org/lionsoul/ip2region/xdb/Segment.java
@@ -89,6 +89,11 @@ public class Segment {
         return Util.ipToString(startIP) + "|" + Util.ipToString(endIP) + "|" + region;
     }
 
+    // check if the an IP address in within this segment
+    public boolean contains(final byte[] ip) {
+        return Util.ipCompare(ip, startIP) >= 0 && Util.ipCompare(ip, endIP) <= 0;
+    }
+
     // parser the Segment from an input string
     public static Segment parse(String input) throws Exception {
         final String[] ps = input.trim().split("\\|", 3);
diff --git a/maker/java/src/test/java/org/lionsoul/ip2region/xdb/MakerTest.java b/maker/java/src/test/java/org/lionsoul/ip2region/xdb/MakerTest.java
new file mode 100644
index 0000000..291d101
--- /dev/null
+++ b/maker/java/src/test/java/org/lionsoul/ip2region/xdb/MakerTest.java
@@ -0,0 +1,15 @@
+package org.lionsoul.ip2region.xdb;
+
+import org.junit.Test;
+
+public class MakerTest {
+
+    private static final Log log = Log.getLogger(MakerTest.class);
+
+    @Test
+    public void testInit() {
+        log.infof("MaxFilePointer(%d bytes): %d", Maker.RuntimePtrSize, Maker.MaxFilePointer);
+        log.infof("MaxFilePoiner(5 bytes): %d", ((1L << (5 * 8)) - 1));
+        log.infof("MaxFilePoiner(6 bytes): %d", ((1L << (6 * 8)) - 1));
+    }
+}