diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/Predicates.java b/src/main/java/xyz/zhouxy/plusone/commons/function/Predicates.java
index e1620f4..adb4989 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/function/Predicates.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/Predicates.java
@@ -42,9 +42,9 @@ public class Predicates {
      *         .and(StringUtils::isNotEmpty);
      * </pre>
      * 
-     * @param <T>
-     * @param predicate
-     * @return
+     * @param <T>       目标类型
+     * @param predicate 原 {@link Predicate} 实例
+     * @return 包装的 {@link Predicate} 实例
      */
     public static <T> Predicate<T> of(Predicate<? super T> predicate) {
         return predicate::test;
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/jdbc/DbRecord.java b/src/main/java/xyz/zhouxy/plusone/commons/jdbc/DbRecord.java
index 120d26e..a233da4 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/jdbc/DbRecord.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/jdbc/DbRecord.java
@@ -59,7 +59,7 @@ public class DbRecord extends AbstractMapWrapper<String, Object, DbRecord> {
     public <T> Set<T> getValueAsSet(String key) {
         return this.<Collection<T>>getAndConvert(key)
                 .map(l -> (l instanceof Set) ? (Set<T>) l : new HashSet<>(l))
-                .orElse(Collections.<T>emptySet());
+                .orElse(Collections.emptySet());
     }
 
     public OptionalInt getValueAsInt(String key) {
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/jdbc/SimpleJdbcTemplate.java b/src/main/java/xyz/zhouxy/plusone/commons/jdbc/SimpleJdbcTemplate.java
index 51d274f..819168d 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/jdbc/SimpleJdbcTemplate.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/jdbc/SimpleJdbcTemplate.java
@@ -213,7 +213,7 @@ public class SimpleJdbcTemplate {
             int executeCount = params.size() / batchSize;
             executeCount = (params.size() % batchSize == 0) ? executeCount : (executeCount + 1);
             List<int[]> result = Lists.newArrayListWithCapacity(executeCount);
-            
+
             try (PreparedStatement stmt = this.conn.prepareStatement(sql)) {
                 int i = 0;
                 for (Object[] ps : params) {
@@ -247,7 +247,7 @@ public class SimpleJdbcTemplate {
         }
 
         @FunctionalInterface
-        public static interface IAtom<T extends Exception> {
+        public interface IAtom<T extends Exception> {
             @SuppressWarnings("all")
             void execute() throws SQLException, T;
         }
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/MapWrapper.java b/src/main/java/xyz/zhouxy/plusone/commons/util/MapWrapper.java
index 62a936f..7838df2 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/MapWrapper.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/MapWrapper.java
@@ -49,7 +49,7 @@ public final class MapWrapper<K, V> extends AbstractMapWrapper<K, V, MapWrapper<
         return new Builder<>(new HashMap<>(initialCapacity, loadFactor));
     }
 
-    public static <K, V> Builder<K, V> wrapTreeMap() {
+    public static <K extends Comparable<? super K>, V> Builder<K, V> wrapTreeMap() {
         return new Builder<>(new TreeMap<>());
     }
 
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/OptionalUtil.java b/src/main/java/xyz/zhouxy/plusone/commons/util/OptionalUtil.java
index 05808a7..57c4660 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/OptionalUtil.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/OptionalUtil.java
@@ -55,16 +55,16 @@ public class OptionalUtil {
     }
 
     /**
-     * 将 {@code Optional<Integer>} 转为 {@link OptionalInt}。
+     * 将 {@code Optional<Integer>} 对象转为 {@link OptionalInt} 对象。
      * <p>
      * {@code Optional<Integer>} 将整数包装了两次，改为使用 {@link OptionalInt} 包装其中的整数数据。
      * </p>
      * 
-     * @param value 包装对象
+     * @param optionalObj {@code Optional<Integer>} 对象
      * @return {@link OptionalInt} 实例
      */
-    public static OptionalInt toOptionalInt(Optional<Integer> objectOptional) {
-        return optionalOf(objectOptional.orElse(null));
+    public static OptionalInt toOptionalInt(Optional<Integer> optionalObj) {
+        return optionalOf(optionalObj.orElse(null));
     }
 
     /**
@@ -87,11 +87,11 @@ public class OptionalUtil {
      * {@code Optional<Long>} 将整数包装了两次，改为使用 {@link OptionalLong} 包装其中的整数数据。
      * </p>
      * 
-     * @param value 包装对象
+     * @param optionalObj 包装对象
      * @return {@link OptionalLong} 实例
      */
-    public static OptionalLong toOptionalLong(Optional<Long> objectOptional) {
-        return optionalOf(objectOptional.orElse(null));
+    public static OptionalLong toOptionalLong(Optional<Long> optionalObj) {
+        return optionalOf(optionalObj.orElse(null));
     }
 
     /**
@@ -114,11 +114,11 @@ public class OptionalUtil {
      * {@code Optional<Double>} 将整数包装了两次，改为使用 {@link OptionalDouble} 包装其中的整数数据。
      * </p>
      * 
-     * @param value 包装对象
+     * @param optionalObj 包装对象
      * @return {@link OptionalDouble} 实例
      */
-    public static OptionalDouble toOptionalDouble(Optional<Double> objectOptional) {
-        return optionalOf(objectOptional.orElse(null));
+    public static OptionalDouble toOptionalDouble(Optional<Double> optionalObj) {
+        return optionalOf(optionalObj.orElse(null));
     }
 
     /**
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/SnowflakeIdGenerator.java b/src/main/java/xyz/zhouxy/plusone/commons/util/SnowflakeIdGenerator.java
index 4e410b2..810eee7 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/SnowflakeIdGenerator.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/SnowflakeIdGenerator.java
@@ -42,10 +42,10 @@ public class SnowflakeIdGenerator {
     private static final long SEQUENCE_MASK = -1L ^ (-1L << SEQUENCE_BITS);
 
     /** 工作机器 ID (0~31) */
-    private long workerId;
+    private final long workerId;
 
     /** 数据中心 ID (0~31) */
-    private long datacenterId;
+    private final long datacenterId;
 
     /** 毫秒内序列 (0~4095) */
     private long sequence = 0L;
@@ -78,7 +78,6 @@ public class SnowflakeIdGenerator {
      * 获得下一个ID (该方法是线程安全的)
      * 
      * @return SnowflakeId
-     * @throws InterruptedException
      */
     public synchronized long nextId() {
         long timestamp = timeGen();
diff --git a/src/test/java/xyz/zhouxy/plusone/commons/util/SimpleJdbcTemplateTests.java b/src/test/java/xyz/zhouxy/plusone/commons/util/SimpleJdbcTemplateTests.java
index 02a87ab..d8574e1 100644
--- a/src/test/java/xyz/zhouxy/plusone/commons/util/SimpleJdbcTemplateTests.java
+++ b/src/test/java/xyz/zhouxy/plusone/commons/util/SimpleJdbcTemplateTests.java
@@ -27,7 +27,7 @@ class SimpleJdbcTemplateTests {
 
     private static final Logger log = LoggerFactory.getLogger(SimpleJdbcTemplateTests.class);
 
-    DataSource dataSource;
+    final DataSource dataSource;
 
     String[] cStruct = {
             "id",
diff --git a/src/test/java/xyz/zhouxy/plusone/commons/util/TreeBuilderTests.java b/src/test/java/xyz/zhouxy/plusone/commons/util/TreeBuilderTests.java
index 446ec35..dd2c063 100644
--- a/src/test/java/xyz/zhouxy/plusone/commons/util/TreeBuilderTests.java
+++ b/src/test/java/xyz/zhouxy/plusone/commons/util/TreeBuilderTests.java
@@ -31,7 +31,7 @@ class TreeBuilderTests {
                 MenuItem.of("C", "C2", "二级菜单C2", "/c/c2"),
                 MenuItem.of("C", "C3", "二级菜单C3", "/c/c3")
         );
-        List<Menu> menuTree = new TreeBuilder<Menu, String>(
+        List<Menu> menuTree = new TreeBuilder<>(
                 menus,
                 Menu::getMenuCode,
                 Menu::getParentMenuCode,