diff --git a/Java/README.md b/Java/README.md
index 51a6740..e914e60 100644
--- a/Java/README.md
+++ b/Java/README.md
@@ -8,22 +8,23 @@ JDK 1.8+
 <dependency>
 	<groupId>com.github.yitter</groupId>
 	<artifactId>yitter-idgenerator</artifactId>
-	<version>1.0.2</version>
+	<version>1.0.3</version>
 </dependency>
 ```
 
 ## 调用示例
 ```
-// 全局初始化设置WorkerId，默认最大2^16-1。（初始化过程全局只需一次，且必须最先设置）
+// 全局初始化设置WorkerId，默认最大2^16-1，可通过调整 WorkerIdBitLength 增加最大值
 IdGeneratorOptions options = new IdGeneratorOptions();
 options.WorkerId = 1;
 YitIdHelper.setIdGenerator(options);
+// 以上初始化过程全局只需一次，且必须最先设置
 
-// 初始化以后，就可以在需要的地方调用方法生成ID。
+// 初始化以后，即可在需要生成ID的地方，调用以下方法。
 long newId = YitIdHelper.nextId();
 
 ```
-如果基于DI框架集成，可以参考 YitIdHelper 去管理 IdGenerator 对象，必须使用**单例**模式。
+如果基于DI框架集成，可以参考 YitIdHelper 去管理 IdGenerator 对象，须使用**单例**模式。
 
 
 ## options 默认值及说明
diff --git a/Java/source/pom.xml b/Java/source/pom.xml
index 3d80c29..6fb9e8e 100644
--- a/Java/source/pom.xml
+++ b/Java/source/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>com.github.yitter</groupId>
     <artifactId>yitter-idgenerator</artifactId>
-    <version>1.0.3-SNAPSHOT</version>
+    <version>1.0.4-SNAPSHOT</version>
     <packaging>jar</packaging>
 
     <name>yitter-idgenerator</name>
diff --git a/Java/source/src/main/java/com/github/yitter/contract/IdGeneratorOptions.java b/Java/source/src/main/java/com/github/yitter/contract/IdGeneratorOptions.java
index 029b482..8c56dae 100644
--- a/Java/source/src/main/java/com/github/yitter/contract/IdGeneratorOptions.java
+++ b/Java/source/src/main/java/com/github/yitter/contract/IdGeneratorOptions.java
@@ -51,7 +51,7 @@ public class IdGeneratorOptions {
 
     /**
      * 鏈�灏忓簭鍒楁暟锛堝惈锛�
-     * 榛樿5锛屼笉灏忎簬1锛屼笉澶т簬MaxSeqNumber
+     * 榛樿5锛屼笉灏忎簬5锛屼笉澶т簬MaxSeqNumber
      */
     public short MinSeqNumber = 5;
 
diff --git a/Java/source/src/main/java/com/github/yitter/core/SnowWorkerM1.java b/Java/source/src/main/java/com/github/yitter/core/SnowWorkerM1.java
index a6c8c85..be45ebc 100644
--- a/Java/source/src/main/java/com/github/yitter/core/SnowWorkerM1.java
+++ b/Java/source/src/main/java/com/github/yitter/core/SnowWorkerM1.java
@@ -63,7 +63,7 @@ public class SnowWorkerM1 implements ISnowWorker {
         WorkerId = options.WorkerId;
         WorkerIdBitLength = options.WorkerIdBitLength == 0 ? 6 : options.WorkerIdBitLength;
         SeqBitLength = options.SeqBitLength == 0 ? 6 : options.SeqBitLength;
-        MaxSeqNumber = options.MaxSeqNumber > 0 ? options.MaxSeqNumber : (int) Math.pow(2, SeqBitLength) - 1;
+        MaxSeqNumber = options.MaxSeqNumber > 0 ? options.MaxSeqNumber : (1 << SeqBitLength) - 1;
         MinSeqNumber = options.MinSeqNumber;
         TopOverCostCount = options.TopOverCostCount;
         BaseTime = options.BaseTime != 0 ? options.BaseTime : 1582136402000L;
diff --git a/Java/source/src/main/java/com/github/yitter/idgen/DefaultIdGenerator.java b/Java/source/src/main/java/com/github/yitter/idgen/DefaultIdGenerator.java
index 583f205..a293a02 100644
--- a/Java/source/src/main/java/com/github/yitter/idgen/DefaultIdGenerator.java
+++ b/Java/source/src/main/java/com/github/yitter/idgen/DefaultIdGenerator.java
@@ -47,17 +47,15 @@ public class DefaultIdGenerator implements IIdGenerator {
         }
 
         int maxValue = maxSeqNumber;
-        if (options.MinSeqNumber < 1 || options.MinSeqNumber > maxValue) {
-            throw new IdGeneratorException("MinSeqNumber error. (range:[1, " + maxValue + "]");
+        if (options.MinSeqNumber < 5 || options.MinSeqNumber > maxValue) {
+            throw new IdGeneratorException("MinSeqNumber error. (range:[5, " + maxValue + "]");
         }
 
         switch (options.Method) {
-            case 1:
-                _SnowWorker = new SnowWorkerM1(options);
-                break;
             case 2:
                 _SnowWorker = new SnowWorkerM2(options);
                 break;
+            case 1:
             default:
                 _SnowWorker = new SnowWorkerM1(options);
                 break;