refactor!: 移除 plusone-commons 及 Guava 依赖，内化工具方法

完全移除对外部工具库 plusone-commons 和 Guava 的编译期依赖，
将所需功能内化实现，使项目成为真正的零依赖轻量级 JDBC 封装库。

- 新增 AssertTools: 断言工具（checkArgument / checkNotNull / checkState / checkCondition）
- 新增 NamingTools: 命名转换（camelToSnake）
- 新增 ThrowingConsumer / ThrowingPredicate: 可抛受检异常的函数式接口
- 新增 AssertToolsTests: 完整覆盖断言工具所有方法及边界场景
- pom.xml 移除 plusone-dependencies BOM，直接声明 jsr305 / test 依赖版本
- DefaultBeanRowMapper 使用 NamingTools.camelToSnake 替代 Guava CaseFormat
- ParamBuilder 内联 Optional 展开逻辑，去除 OptionalTools / CollectionTools
- JdbcOperationSupport 用 null/长度判断替代 ArrayTools.isEmpty/isNotEmpty
- NOTICE 移除第三方依赖声明；README 移除无依赖分支说明
- 测试：新增缩写映射（URL/XML/ID/HTML/HTTP）覆盖、TransactionException 构造器测试

BREAKING CHANGE: BatchUpdateStatus 不再实现 IWithIntCode 接口；
plusone-commons 和 Guava 不再作为传递依赖提供。

NOTICE

@@ -5,36 +5,20 @@ This product is licensed under the Apache License, Version 2.0.
 You may obtain a copy of the License at:
 https://www.apache.org/licenses/LICENSE-2.0
 
-================================================================================
-Third-Party Dependencies
-================================================================================
-
-1. plusone-commons (xyz.zhouxy.plusone:plusone-commons)
-   Copyright ZhouXY
-   Licensed under the Apache License, Version 2.0
-
-2. Google Guava (com.google.guava:guava)
-   Copyright (C) The Guava Authors
-   Licensed under the Apache License, Version 2.0
-
-3. JSR-305 Annotations (com.google.code.findbugs:jsr305)
-   Copyright (C) FindBugs
-   Licensed under the Apache License, Version 2.0
-
 ================================================================================
 Test Dependencies (Not included in distribution)
 ================================================================================
 
-4. JUnit Jupiter (org.junit.jupiter:junit-jupiter)
+1. JUnit Jupiter (org.junit.jupiter:junit-jupiter)
    Copyright 2015-2026 JUnit Team
    Licensed under the Eclipse Public License 2.0
 
-5. Logback (ch.qos.logback:logback-classic)
+2. Logback (ch.qos.logback:logback-classic)
    Copyright (C) 1999-2026, QOS.ch
    Licensed under the Eclipse Public License 1.0
    and GNU Lesser General Public License 2.1
 
-6. H2 Database (com.h2database:h2)
+3. H2 Database (com.h2database:h2)
    Copyright 1999-2026 H2 Database Project
    Licensed under the MPL 2.0 and EPL 1.0
 
@@ -42,6 +26,6 @@ Test Dependencies (Not included in distribution)
 Notes
 ================================================================================
 
-- This project is a lightweight JDBC wrapper designed for legacy projects 
+- This project is a lightweight JDBC wrapper designed for legacy projects
   without ORM frameworks.
 - For learning and reference purposes only.

README.md

@@ -4,8 +4,6 @@
 
 > 注：本项目基于 [Apache License 2.0](https://www.apache.org/licenses/LICENSE-2.0) 开源协议发布。
 
-> 💡 **无外部依赖说明**：主分支（`dev`）的发布版本依赖 `plusone-commons` 工具库（含 Guava）。若您的项目属于不方便引入新依赖的场景（如老项目改造），可使用 `feature/no-dependencies` 分支，直接复制源码进行使用，无需考虑依赖问题。该分支已移除所有编译期与运行期外部依赖，将所需的工具方法（如断言检查）内化实现，仅保留测试相关的依赖项。
-
 ---
 
 ## 1. ✨ 核心特性

pom.xml

@@ -16,7 +16,11 @@
         <maven.compiler.target>8</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
-        <plusone-commons.version>1.1.0-RC2</plusone-commons.version>
+        <!-- Dependency Versions -->
+        <jsr305.version>3.0.2</jsr305.version>
+        <junit-jupiter.version>5.14.4</junit-jupiter.version>
+        <logback.version>1.3.16</logback.version>
+        <h2.version>2.2.224</h2.version>
     </properties>
 
     <licenses>
@@ -40,43 +44,35 @@
         <url>https://gitea.zhouxy.xyz/plusone/simple-jdbc</url>
     </scm>
 
-    <dependencyManagement>
-        <dependencies>
-            <dependency>
-                <groupId>xyz.zhouxy.plusone</groupId>
-                <artifactId>plusone-dependencies</artifactId>
-                <version>${plusone-commons.version}</version>
-                <type>pom</type>
-                <scope>import</scope>
-            </dependency>
-        </dependencies>
-    </dependencyManagement>
-
     <dependencies>
         <dependency>
-            <groupId>xyz.zhouxy.plusone</groupId>
+            <groupId>com.google.code.findbugs</groupId>
-            <artifactId>plusone-commons</artifactId>
+            <artifactId>jsr305</artifactId>
-            <version>${plusone-commons.version}</version>
+            <version>${jsr305.version}</version>
         </dependency>
 
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
+            <version>${junit-jupiter.version}</version>
             <scope>test</scope>
         </dependency>
 
         <dependency>
             <groupId>ch.qos.logback</groupId>
             <artifactId>logback-classic</artifactId>
+            <version>${logback.version}</version>
             <scope>test</scope>
         </dependency>
 
         <dependency>
             <groupId>com.h2database</groupId>
             <artifactId>h2</artifactId>
+            <version>${h2.version}</version>
             <scope>test</scope>
         </dependency>
     </dependencies>
+
     <profiles>
         <profile>
             <id>release</id>

src/main/java/xyz/zhouxy/jdbc/BatchUpdateStatus.java

@@ -15,8 +15,6 @@
  */
 package xyz.zhouxy.jdbc;
 
-import xyz.zhouxy.plusone.commons.base.IWithIntCode;
-
 /**
  * 批量更新状态
  *
@@ -27,7 +25,7 @@ import xyz.zhouxy.plusone.commons.base.IWithIntCode;
  * @see BatchUpdateResult
  * @see BatchUpdateResult#getStatus()
  */
-public enum BatchUpdateStatus implements IWithIntCode {
+public enum BatchUpdateStatus {
 
     /**
      * 成功
@@ -62,9 +60,10 @@ public enum BatchUpdateStatus implements IWithIntCode {
     }
 
     /**
-     * {@inheritDoc}
+     * 获取状态码
+     *
+     * @return 状态码
      */
-    @Override
     public int getCode() {
         return code;
     }

src/main/java/xyz/zhouxy/jdbc/DefaultBeanRowMapper.java

@@ -34,9 +34,7 @@ import java.util.stream.Collectors;
 
 import javax.annotation.Nullable;
 
-import com.google.common.base.CaseFormat;
+import xyz.zhouxy.jdbc.util.NamingTools;
-
-import xyz.zhouxy.plusone.commons.annotation.StaticFactoryMethod;
 
 /**
  * DefaultBeanRowMapper
@@ -90,7 +88,6 @@ public class DefaultBeanRowMapper<T> implements RowMapper<T> {
      * @return DefaultBeanRowMapper 对象
      * @throws SQLException 创建 {@code DefaultBeanRowMapper} 出现错误的异常时抛出
      */
-    @StaticFactoryMethod(DefaultBeanRowMapper.class)
     public static <T> DefaultBeanRowMapper<T> of(Class<T> beanType) throws SQLException {
         return of(beanType, null);
     }
@@ -104,7 +101,6 @@ public class DefaultBeanRowMapper<T> implements RowMapper<T> {
      * @return {@code DefaultBeanRowMapper} 对象
      * @throws SQLException 创建 {@code DefaultBeanRowMapper} 出现错误的异常时抛出
      */
-    @StaticFactoryMethod(DefaultBeanRowMapper.class)
     public static <T> DefaultBeanRowMapper<T> of(Class<T> beanType, @Nullable Map<String, String> propertyColMap)
             throws SQLException {
         try {
@@ -167,14 +163,14 @@ public class DefaultBeanRowMapper<T> implements RowMapper<T> {
         // Bean 的属性名为小驼峰，对应的列名为下划线
         Function<? super PropertyDescriptor, String> keyMapper;
         if (propertyColMap == null || propertyColMap.isEmpty()) {
-            keyMapper = p -> CaseFormat.LOWER_CAMEL.to(CaseFormat.LOWER_UNDERSCORE, p.getName());
+            keyMapper = p -> NamingTools.camelToSnake(p.getName());
         }
         else {
             keyMapper = p -> {
                 String propertyName = p.getName();
                 String colName = propertyColMap.get(propertyName);
                 return colName != null ? colName
-                    : CaseFormat.LOWER_CAMEL.to(CaseFormat.LOWER_UNDERSCORE, propertyName);
+                    : NamingTools.camelToSnake(propertyName);
             };
         }
         return Arrays.stream(propertyDescriptors)

src/main/java/xyz/zhouxy/jdbc/JdbcOperationSupport.java

@@ -16,8 +16,8 @@
 
 package xyz.zhouxy.jdbc;
 
-import static xyz.zhouxy.plusone.commons.util.AssertTools.checkArgument;
+import static xyz.zhouxy.jdbc.util.AssertTools.checkArgument;
-import static xyz.zhouxy.plusone.commons.util.AssertTools.checkArgumentNotNull;
+import static xyz.zhouxy.jdbc.util.AssertTools.checkArgumentNotNull;
 
 import java.sql.BatchUpdateException;
 import java.sql.Connection;
@@ -37,8 +37,6 @@ import java.util.List;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
-import xyz.zhouxy.plusone.commons.util.ArrayTools;
-
 /**
  * JdbcOperationSupport
  *
@@ -162,7 +160,7 @@ class JdbcOperationSupport {
             throws SQLException {
         assertConnectionNotNull(conn);
         assertSqlNotNull(sql);
-        if (ArrayTools.isNotEmpty(params)) {
+        if (params != null && params.length > 0) {
             try (PreparedStatement stmt = conn.prepareStatement(sql)) {
                 fillStatement(stmt, params);
                 return stmt.executeUpdate();
@@ -191,7 +189,7 @@ class JdbcOperationSupport {
         assertConnectionNotNull(conn);
         assertSqlNotNull(sql);
         assertRowMapperNotNull(rowMapper);
-        if (ArrayTools.isNotEmpty(params)) {
+        if (params != null && params.length > 0) {
             try (PreparedStatement stmt = conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)) {
                 fillStatement(stmt, params);
                 stmt.executeUpdate();
@@ -308,7 +306,7 @@ class JdbcOperationSupport {
                                        @Nullable Object[] params,
                                        @Nonnull ResultHandler<T> resultHandler)
             throws SQLException {
-        if (ArrayTools.isNotEmpty(params)) {
+        if (params != null && params.length > 0) {
             try (PreparedStatement stmt = createPreparedStatementInternal(conn, sql, params);
                  ResultSet rs = stmt.executeQuery()) {
                 return resultHandler.handle(rs);

src/main/java/xyz/zhouxy/jdbc/ParamBuilder.java

@@ -29,10 +29,7 @@ import java.util.OptionalLong;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
-import xyz.zhouxy.plusone.commons.collection.CollectionTools;
+import xyz.zhouxy.jdbc.util.AssertTools;
-import xyz.zhouxy.plusone.commons.util.ArrayTools;
-import xyz.zhouxy.plusone.commons.util.AssertTools;
-import xyz.zhouxy.plusone.commons.util.OptionalTools;
 
 /**
  * ParamBuilder
@@ -66,7 +63,7 @@ public class ParamBuilder {
      * @return 参数数组
      */
     public static Object[] buildParams(final Object... params) {
-        if (ArrayTools.isEmpty(params)) {
+        if (params == null || params.length == 0) {
             return EMPTY_OBJECT_ARRAY;
         }
         return Arrays.stream(params)
@@ -91,16 +88,16 @@ public class ParamBuilder {
             return param;
         }
         if (param instanceof Optional) {
-            return OptionalTools.orElseNull((Optional<?>) param);
+            return ((Optional<?>) param).orElse(null);
         }
         if (param instanceof OptionalInt) {
-            return OptionalTools.toInteger((OptionalInt) param);
+            return ((OptionalInt) param).isPresent() ? ((OptionalInt) param).getAsInt() : null;
         }
         if (param instanceof OptionalLong) {
-            return OptionalTools.toLong((OptionalLong) param);
+            return ((OptionalLong) param).isPresent() ? ((OptionalLong) param).getAsLong() : null;
         }
         if (param instanceof OptionalDouble) {
-            return OptionalTools.toDouble((OptionalDouble) param);
+            return ((OptionalDouble) param).isPresent() ? ((OptionalDouble) param).getAsDouble() : null;
         }
         return param;
     }
@@ -121,7 +118,7 @@ public class ParamBuilder {
     public static <T> List<Object[]> buildBatchParams(final Collection<T> c, final Function<T, Object[]> func) {
         AssertTools.checkNotNull(c, "The collection can not be null.");
         AssertTools.checkNotNull(func, "The func can not be null.");
-        if (CollectionTools.isEmpty(c)) {
+        if (c.isEmpty()) {
             return Collections.emptyList();
         }
         return c.stream().map(func).collect(Collectors.toList());

src/main/java/xyz/zhouxy/jdbc/SimpleJdbcTemplate.java

@@ -26,7 +26,7 @@ import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import javax.sql.DataSource;
 
-import xyz.zhouxy.plusone.commons.util.AssertTools;
+import xyz.zhouxy.jdbc.util.AssertTools;
 
 /**
  * JDBC 操作的模板类，对原生 JDBC 进行轻量封装，提供查询、更新、批量操作等便捷方法。

src/main/java/xyz/zhouxy/jdbc/ThrowingConsumer.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2026-present ZhouXY
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xyz.zhouxy.jdbc;
+
+/**
+ * 可抛出受检异常的函数式接口。
+ *
+ * <p>
+ * 类似于 {@link java.util.function.Consumer}，但 {@code accept} 方法允许抛出受检异常。
+ * </p>
+ *
+ * @param <T> 输入类型
+ * @param <E> 允许抛出的异常类型
+ * @author ZhouXY
+ * @since 1.1.0
+ */
+@FunctionalInterface
+public interface ThrowingConsumer<T, E extends Exception> {
+
+    /**
+     * 对给定参数执行此操作。
+     *
+     * @param t 输入参数
+     * @throws E 异常
+     */
+    void accept(T t) throws E;
+}

src/main/java/xyz/zhouxy/jdbc/ThrowingPredicate.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2026-present ZhouXY
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xyz.zhouxy.jdbc;
+
+/**
+ * 可抛出受检异常的谓词函数式接口。
+ *
+ * <p>
+ * 类似于 {@link java.util.function.Predicate}，但 {@code test} 方法允许抛出受检异常。
+ * </p>
+ *
+ * @param <T> 输入类型
+ * @param <E> 允许抛出的异常类型
+ * @author ZhouXY
+ * @since 1.1.0
+ */
+@FunctionalInterface
+public interface ThrowingPredicate<T, E extends Exception> {
+
+    /**
+     * 对给定参数执行此谓词判断。
+     *
+     * @param t 输入参数
+     * @return 谓词判断结果
+     * @throws E 异常
+     */
+    boolean test(T t) throws E;
+}

src/main/java/xyz/zhouxy/jdbc/TransactionTemplate.java

@@ -26,9 +26,7 @@ import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import javax.sql.DataSource;
 
-import xyz.zhouxy.plusone.commons.function.ThrowingConsumer;
+import xyz.zhouxy.jdbc.util.AssertTools;
-import xyz.zhouxy.plusone.commons.function.ThrowingPredicate;
-import xyz.zhouxy.plusone.commons.util.AssertTools;
 
 /**
  * 事务模板，提供事务执行能力。
@@ -64,7 +62,12 @@ public class TransactionTemplate {
     @Nonnull
     private final DataSource dataSource;
 
-    public TransactionTemplate(@Nonnull DataSource dataSource) {
+    /**
+     * 构造一个 {@code TransactionTemplate} 实例
+     *
+     * @param dataSource 数据源，用于获取数据库连接；不可为 {@code null}
+     */
+    public TransactionTemplate(DataSource dataSource) {
         AssertTools.checkNotNull(dataSource);
         this.dataSource = dataSource;
     }

src/main/java/xyz/zhouxy/jdbc/util/AssertTools.java

@@ -0,0 +1,334 @@
+/*
+ * Copyright 2024-present ZhouXY
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xyz.zhouxy.jdbc.util;
+
+import java.util.function.Supplier;
+
+/**
+ * 断言工具
+ *
+ * <p>
+ * 本工具类不封装过多判断逻辑，鼓励充分使用项目中的工具类进行逻辑判断。
+ *
+ * <pre>
+ * checkArgument(StringUtils.hasText(str), "The argument cannot be blank.");
+ * checkState(ArrayUtils.isNotEmpty(result), "The result cannot be empty.");
+ * checkCondition(!CollectionUtils.isEmpty(roles),
+ *     () -&gt; new InvalidInputException("The roles cannot be empty."));
+ * checkCondition(RegexTools.matches(email, PatternConsts.EMAIL),
+ *     "must be a well-formed email address");
+ * </pre>
+ *
+ * @author ZhouXY
+ */
+public class AssertTools {
+
+    // ================================
+    // #region - Argument
+    // ================================
+
+    /**
+     * 检查实参
+     *
+     * @param condition 判断参数是否符合条件的结果
+     * @throws IllegalArgumentException 当条件不满足时抛出
+     */
+    public static void checkArgument(boolean condition) {
+        if (!condition) {
+            throw new IllegalArgumentException();
+        }
+    }
+
+    /**
+     * 检查实参
+     *
+     * @param condition 判断参数是否符合条件的结果
+     * @param errorMessage 异常信息
+     * @throws IllegalArgumentException 当条件不满足时抛出
+     */
+    public static void checkArgument(boolean condition, String errorMessage) {
+        if (!condition) {
+            throw new IllegalArgumentException(errorMessage);
+        }
+    }
+
+    /**
+     * 检查实参
+     *
+     * @param condition 判断参数是否符合条件的结果
+     * @param errorMessageSupplier 异常信息
+     * @throws IllegalArgumentException 当条件不满足时抛出
+     */
+    public static void checkArgument(boolean condition, Supplier<String> errorMessageSupplier) {
+        if (!condition) {
+            throw new IllegalArgumentException(errorMessageSupplier.get());
+        }
+    }
+
+    /**
+     * 检查实参
+     *
+     * @param condition 判断参数是否符合条件的结果
+     * @param errorMessageTemplate 异常信息模板
+     * @param errorMessageArgs 异常信息参数
+     * @throws IllegalArgumentException 当条件不满足时抛出
+     */
+    public static void checkArgument(boolean condition,
+            String errorMessageTemplate, Object... errorMessageArgs) {
+        if (!condition) {
+            throw new IllegalArgumentException(String.format(errorMessageTemplate, errorMessageArgs));
+        }
+    }
+
+    // ================================
+    // #endregion - Argument
+    // ================================
+
+    // ================================
+    // #region - ArgumentNotNull
+    // ================================
+
+    /**
+     * 判断入参不为 {@code null}
+     *
+     * @param <T> 入参类型
+     * @param obj 入参
+     * @return 校验通过时返回入参
+     * @throws IllegalArgumentException 当 {@code obj} 为 {@code null} 时抛出
+     */
+    public static <T> T checkArgumentNotNull(T obj) {
+        if (obj == null) {
+            throw new IllegalArgumentException();
+        }
+        return obj;
+    }
+
+    /**
+     * 判断入参不为 {@code null}
+     *
+     * @param <T> 入参类型
+     * @param obj 入参
+     * @param errorMessage 异常信息
+     * @return 校验通过时返回入参
+     * @throws IllegalArgumentException 当 {@code obj} 为 {@code null} 时抛出
+     */
+    public static <T> T checkArgumentNotNull(T obj, String errorMessage) {
+        if (obj == null) {
+            throw new IllegalArgumentException(errorMessage);
+        }
+        return obj;
+    }
+
+    /**
+     * 判断入参不为 {@code null}
+     *
+     * @param <T> 入参类型
+     * @param obj 入参
+     * @param errorMessageSupplier 异常信息
+     * @return 校验通过时返回入参
+     * @throws IllegalArgumentException 当 {@code obj} 为 {@code null} 时抛出
+     */
+    public static <T> T checkArgumentNotNull(T obj, Supplier<String> errorMessageSupplier) {
+        if (obj == null) {
+            throw new IllegalArgumentException(errorMessageSupplier.get());
+        }
+        return obj;
+    }
+
+    /**
+     * 判断入参不为 {@code null}
+     *
+     * @param <T> 入参类型
+     * @param obj 入参
+     * @param errorMessageTemplate 异常信息模板
+     * @param errorMessageArgs 异常信息参数
+     * @return 校验通过时返回入参
+     * @throws IllegalArgumentException 当 {@code obj} 为 {@code null} 时抛出
+     */
+    public static <T> T checkArgumentNotNull(T obj,
+            String errorMessageTemplate, Object... errorMessageArgs) {
+        if (obj == null) {
+            throw new IllegalArgumentException(String.format(errorMessageTemplate, errorMessageArgs));
+        }
+        return obj;
+    }
+
+    // ================================
+    // #endregion - ArgumentNotNull
+    // ================================
+
+    // ================================
+    // #region - State
+    // ================================
+
+    /**
+     * 检查状态
+     *
+     * @param condition 判断状态是否符合条件的结果
+     * @throws IllegalStateException 当条件不满足时抛出
+     */
+    public static void checkState(boolean condition) {
+        if (!condition) {
+            throw new IllegalStateException();
+        }
+    }
+
+    /**
+     * 检查状态
+     *
+     * @param condition 判断状态是否符合条件的结果
+     * @param errorMessage 异常信息
+     * @throws IllegalStateException 当条件不满足时抛出
+     */
+    public static void checkState(boolean condition, String errorMessage) {
+        if (!condition) {
+            throw new IllegalStateException(errorMessage);
+        }
+    }
+
+    /**
+     * 检查状态
+     *
+     * @param condition 判断状态是否符合条件的结果
+     * @param errorMessageSupplier 异常信息
+     * @throws IllegalStateException 当条件不满足时抛出
+     */
+    public static void checkState(boolean condition, Supplier<String> errorMessageSupplier) {
+        if (!condition) {
+            throw new IllegalStateException(errorMessageSupplier.get());
+        }
+    }
+
+    /**
+     * 检查状态
+     *
+     * @param condition 判断状态是否符合条件的结果
+     * @param errorMessageTemplate 异常信息模板
+     * @param errorMessageArgs 异常信息参数
+     * @throws IllegalStateException 当条件不满足时抛出
+     */
+    public static void checkState(boolean condition,
+            String errorMessageTemplate, Object... errorMessageArgs) {
+        if (!condition) {
+            throw new IllegalStateException(String.format(errorMessageTemplate, errorMessageArgs));
+        }
+    }
+
+    // ================================
+    // #endregion - State
+    // ================================
+
+    // ================================
+    // #region - NotNull
+    // ================================
+
+    /**
+     * 判空
+     *
+     * @param <T> 入参类型
+     * @param obj 入参
+     * @throws NullPointerException 当 {@code obj} 为 {@code null} 时抛出
+     */
+    public static <T> void checkNotNull(T obj) {
+        if (obj == null) {
+            throw new NullPointerException();
+        }
+    }
+
+    /**
+     * 判空
+     *
+     * @param <T> 入参类型
+     * @param obj 入参
+     * @param errorMessage 异常信息
+     * @throws NullPointerException 当 {@code obj} 为 {@code null} 时抛出
+     */
+    public static <T> void checkNotNull(T obj, String errorMessage) {
+        if (obj == null) {
+            throw new NullPointerException(errorMessage);
+        }
+    }
+
+    /**
+     * 判空
+     *
+     * @param <T> 入参类型
+     * @param obj 入参
+     * @param errorMessageSupplier 异常信息
+     * @throws NullPointerException 当 {@code obj} 为 {@code null} 时抛出
+     */
+    public static <T> void checkNotNull(T obj, Supplier<String> errorMessageSupplier) {
+        if (obj == null) {
+            throw new NullPointerException(errorMessageSupplier.get());
+        }
+    }
+
+    /**
+     * 判空
+     *
+     * @param <T> 入参类型
+     * @param obj 入参
+     * @param errorMessageTemplate 异常信息模板
+     * @param errorMessageArgs 异常信息参数
+     * @throws NullPointerException 当 {@code obj} 为 {@code null} 时抛出
+     */
+    public static <T> void checkNotNull(T obj,
+            String errorMessageTemplate, Object... errorMessageArgs) {
+        if (obj == null) {
+            throw new NullPointerException(String.format(errorMessageTemplate, errorMessageArgs));
+        }
+    }
+
+    // ================================
+    // #endregion - NotNull
+    // ================================
+
+    // ================================
+    // #region - Condition
+    // ================================
+
+    /**
+     * 当条件不满足时抛出异常。
+     *
+     * @param <T> 异常类型
+     * @param condition 条件
+     * @param e 异常
+     * @throws T 当条件不满足时抛出异常
+     */
+    public static <T extends Exception> void checkCondition(boolean condition, Supplier<T> e)
+            throws T {
+        if (!condition) {
+            throw e.get();
+        }
+    }
+
+    // ================================
+    // #endregion
+    // ================================
+
+    // ================================
+    // #region - constructor
+    // ================================
+
+    private AssertTools() {
+        throw new IllegalStateException("Utility class");
+    }
+
+    // ================================
+    // #endregion
+    // ================================
+}

src/main/java/xyz/zhouxy/jdbc/util/NamingTools.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright 2026-present ZhouXY
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xyz.zhouxy.jdbc.util;
+
+/**
+ * 字符串工具
+ *
+ * @author ZhouXY
+ * @since 1.0.0
+ */
+public class NamingTools {
+
+    /**
+     * 将小驼峰命名转换为小写下划线命名（snake_case）。
+     *
+     * <p>转换规则：
+     * <ul>
+     * <li>小写→大写边界插入下划线：{@code userName → user_name}</li>
+     * <li>连续大写缩写视为整体，在其末尾小写边界插入下划线：{@code XMLParser → xml_parser}</li>
+     * <li>纯小写保持不变：{@code username → username}</li>
+     * <li>{@code null} 或空字符串返回原值</li>
+     * </ul>
+     *
+     * @param camelCase 小驼峰命名字符串，可空
+     * @return snake_case 命名字符串；{@code null} 输入返回 {@code null}
+     */
+    public static String camelToSnake(String camelCase) {
+        if (camelCase == null || camelCase.isEmpty()) {
+            return camelCase;
+        }
+
+        StringBuilder sb = new StringBuilder(camelCase.length() * 2);
+        int len = camelCase.length();
+
+        for (int i = 0; i < len; i++) {
+            char c = camelCase.charAt(i);
+            if (isUpperCaseAscii(c)) {
+                if (shouldInsertUnderscore(camelCase, i)) {
+                    sb.append('_');
+                }
+                sb.append((char) (c + 32)); // 转小写
+            } else {
+                sb.append(c);
+            }
+        }
+        return sb.toString();
+    }
+
+    private static boolean shouldInsertUnderscore(String str, int index) {
+        if (index == 0) {
+            return false;
+        }
+
+        char prev = str.charAt(index - 1);
+        char next = (index + 1 < str.length()) ? str.charAt(index + 1) : 0;
+
+        boolean prevIsBoundary = !isUpperCaseAscii(prev);
+        boolean nextIsLower = isLowerCaseAscii(next);
+
+        return prevIsBoundary || nextIsLower;
+    }
+
+    private static boolean isUpperCaseAscii(char c) {
+        return c >= 'A' && c <= 'Z';
+    }
+
+    private static boolean isLowerCaseAscii(char c) {
+        return c >= 'a' && c <= 'z';
+    }
+
+    // ================================
+    // #region - constructor
+    // ================================
+
+    private NamingTools() {
+        throw new IllegalStateException("Utility class");
+    }
+
+    // ================================
+    // #endregion
+    // ================================
+}

src/test/java/xyz/zhouxy/jdbc/test/BatchUpdateTest.java

@@ -6,6 +6,7 @@ import static xyz.zhouxy.jdbc.ParamBuilder.*;
 import java.sql.SQLException;
 import java.sql.Statement;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
@@ -16,8 +17,6 @@ import org.junit.jupiter.api.Test;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import com.google.common.collect.Lists;
-
 import xyz.zhouxy.jdbc.BatchUpdateErrorInfo;
 import xyz.zhouxy.jdbc.BatchUpdateResult;
 import xyz.zhouxy.jdbc.BatchUpdateStatus;
@@ -170,7 +169,7 @@ class BatchUpdateTest extends BaseH2Test {
     // #region - 包含错误数据
     // ================================
 
-    final List<User> userListContainingInvalidData = Lists.newArrayList(
+    final List<User> userListContainingInvalidData = Arrays.asList(
             // batch 0
             new User("test_0001", "test_0001@example.com", 1, 1L, true),
             new User("test_0002", "test_0002@example.com", 1, 1L, true),

src/test/java/xyz/zhouxy/jdbc/test/RowMapperTest.java

@@ -157,6 +157,63 @@ class RowMapperTest extends BaseH2Test {
         assertEquals("alice", user.get().getUsername());
     }
 
+    // ==================== DefaultBeanRowMapper 连续大写缩写映射 ====================
+
+    @Test
+    @DisplayName("DefaultBeanRowMapper：连续大写缩写属性正确映射为 snake_case")
+    void testDefaultBeanRowMapperAcronymMapping() throws SQLException {
+        SimpleJdbcTemplate template = createTemplate();
+
+        // 创建测试表，列名使用 snake_case
+        template.update("CREATE TABLE acronym_test ("
+                + "id BIGINT AUTO_INCREMENT PRIMARY KEY,"
+                + "home_url VARCHAR(100),"
+                + "xml_parser VARCHAR(100),"
+                + "parse_url VARCHAR(100),"
+                + "user_id VARCHAR(100),"
+                + "parse_html VARCHAR(100),"
+                + "multi_http_client VARCHAR(100))");
+        template.update(
+                "INSERT INTO acronym_test (home_url, xml_parser, parse_url, user_id, parse_html, multi_http_client)"
+                        + " VALUES (?, ?, ?, ?, ?, ?)",
+                new Object[]{"https://example.com", "SAXParser", "/api/v1",
+                        "user-001", "<div>test</div>", "ApacheHttpClient"});
+
+        RowMapper<AcronymBean> rowMapper = RowMapper.beanRowMapper(AcronymBean.class);
+        Optional<AcronymBean> result = template.queryFirst(
+                "SELECT * FROM acronym_test WHERE id = ?",
+                new Object[]{1L}, rowMapper);
+
+        assertTrue(result.isPresent());
+        AcronymBean bean = result.get();
+        assertEquals("https://example.com", bean.getHomeURL());
+        assertEquals("SAXParser", bean.getXmlParser());
+        assertEquals("/api/v1", bean.getParseURL());
+        assertEquals("user-001", bean.getUserID());
+        assertEquals("<div>test</div>", bean.getParseHTML());
+        assertEquals("ApacheHttpClient", bean.getMultiHttpClient());
+
+        logger.info("缩写映射: homeURL={}, xmlParser={}, parseURL={}, userID={}, parseHTML={}, multiHttpClient={}",
+                bean.getHomeURL(), bean.getXmlParser(), bean.getParseURL(),
+                bean.getUserID(), bean.getParseHTML(), bean.getMultiHttpClient());
+    }
+
+    @Test
+    @DisplayName("DefaultBeanRowMapper：纯小写属性名映射为同名列")
+    void testDefaultBeanRowMapperAllLowercaseMapping() throws SQLException {
+        // 通过 User Bean 验证纯小写属性映射（username → username, email → email）
+        SimpleJdbcTemplate template = createTemplate();
+        RowMapper<User> rowMapper = RowMapper.beanRowMapper(User.class);
+
+        Optional<User> user = template.queryFirst(
+                "SELECT username, email FROM users WHERE username = ?",
+                new Object[]{"alice"}, rowMapper);
+
+        assertTrue(user.isPresent());
+        assertEquals("alice", user.get().getUsername());
+        assertEquals("alice@example.com", user.get().getEmail());
+    }
+
     // ==================== HASH_MAP_MAPPER ====================
 
     @Test
@@ -253,4 +310,74 @@ class RowMapperTest extends BaseH2Test {
             this.name = name;
         }
     }
+
+    /**
+     * 包含连续大写缩写属性的 Bean，用于验证 camelToSnake 的缩写处理。
+     *
+     * <p>覆盖场景：
+     * <ul>
+     * <li>homeURL — 缩写在末尾（三字母 URL）</li>
+     * <li>xmlParser — 缩写在前（三字母 XML）</li>
+     * <li>parseURL — 缩写在末尾</li>
+     * <li>userID — 两字母缩写在末尾（ID）</li>
+     * <li>parseHTML — 四字母缩写在末尾（HTML）</li>
+     * <li>multiHttpClient — 缩写夹在词中（HTTP）</li>
+     * </ul>
+     */
+    public static class AcronymBean {
+        private String homeURL;
+        private String xmlParser;
+        private String parseURL;
+        private String userID;
+        private String parseHTML;
+        private String multiHttpClient;
+
+        public String getHomeURL() {
+            return homeURL;
+        }
+
+        public void setHomeURL(String homeURL) {
+            this.homeURL = homeURL;
+        }
+
+        public String getXmlParser() {
+            return xmlParser;
+        }
+
+        public void setXmlParser(String xmlParser) {
+            this.xmlParser = xmlParser;
+        }
+
+        public String getParseURL() {
+            return parseURL;
+        }
+
+        public void setParseURL(String parseURL) {
+            this.parseURL = parseURL;
+        }
+
+        public String getUserID() {
+            return userID;
+        }
+
+        public void setUserID(String userID) {
+            this.userID = userID;
+        }
+
+        public String getParseHTML() {
+            return parseHTML;
+        }
+
+        public void setParseHTML(String parseHTML) {
+            this.parseHTML = parseHTML;
+        }
+
+        public String getMultiHttpClient() {
+            return multiHttpClient;
+        }
+
+        public void setMultiHttpClient(String multiHttpClient) {
+            this.multiHttpClient = multiHttpClient;
+        }
+    }
 }

src/test/java/xyz/zhouxy/jdbc/test/TransactionTest.java

@@ -234,6 +234,15 @@ class TransactionTest extends BaseH2Test {
 
     // ==================== TransactionException ====================
 
+    @Test
+    @DisplayName("TransactionException：单参构造器（仅 cause）")
+    void testTransactionExceptionSingleArg() {
+        RuntimeException cause = new RuntimeException("原始异常");
+        TransactionException ex = new TransactionException(cause);
+        assertEquals("Transaction failed during execution", ex.getMessage());
+        assertSame(cause, ex.getCause());
+    }
+
     @Test
     @DisplayName("TransactionException：双参构造器")
     void testTransactionExceptionWithMessage() {
@@ -242,4 +251,12 @@ class TransactionTest extends BaseH2Test {
         assertEquals("自定义消息", ex.getMessage());
         assertSame(cause, ex.getCause());
     }
+
+    @Test
+    @DisplayName("TransactionException：null cause")
+    void testTransactionExceptionNullCause() {
+        TransactionException ex = new TransactionException(null);
+        assertEquals("Transaction failed during execution", ex.getMessage());
+        assertNull(ex.getCause());
+    }
 }

src/test/java/xyz/zhouxy/jdbc/test/util/AssertToolsTests.java

@@ -0,0 +1,522 @@
+/*
+ * Copyright 2024-2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package xyz.zhouxy.jdbc.test.util;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static xyz.zhouxy.jdbc.util.AssertTools.*;
+
+import java.lang.reflect.Constructor;
+import java.time.LocalDate;
+import java.util.Arrays;
+import java.util.function.Supplier;
+
+import org.junit.jupiter.api.Test;
+
+import xyz.zhouxy.jdbc.util.AssertTools;
+
+class AssertToolsTests {
+
+    // #region - Argument
+
+    @Test
+    void testCheckArgument_true() {
+        checkArgument(true);
+    }
+
+    @Test
+    void testCheckArgument_true_withMessage() {
+        final String IGNORE_ME = "IGNORE_ME"; // NOSONAR
+        checkArgument(true, IGNORE_ME);
+    }
+
+    @Test
+    void testCheckArgument_true_withNullMessage() {
+        final String IGNORE_ME = null; // NOSONAR
+        checkArgument(true, IGNORE_ME);
+    }
+
+    @Test
+    void testCheckArgument_true_withMessageSupplier() {
+        checkArgument(true, () -> "Error message: " + LocalDate.now());
+    }
+
+    @Test
+    void testCheckArgument_true_withNullMessageSupplier() {
+        final Supplier<String> IGNORE_ME = null; // NOSONAR
+        checkArgument(true, IGNORE_ME);
+    }
+
+    @Test
+    void testCheckArgument_true_withMessageFormat() {
+        LocalDate today = LocalDate.now();
+        checkArgument(true, "String format: %s", today);
+    }
+
+    @Test
+    void testCheckArgument_true_withNullMessageFormat() {
+        checkArgument(true, null, LocalDate.now());
+    }
+
+    @Test
+    void testCheckArgument_false() {
+        final IllegalArgumentException e = assertThrows(IllegalArgumentException.class,
+                () -> checkArgument(false));
+
+        assertNull(e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckArgument_false_withMessage() {
+        final String message = "testCheckArgument_false_withMessage";
+
+        final IllegalArgumentException e = assertThrows(IllegalArgumentException.class,
+                () -> checkArgument(false, message));
+
+        assertEquals(message, e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckArgument_false_withNullMessage() {
+        final String message = null;
+
+        final IllegalArgumentException e = assertThrows(IllegalArgumentException.class,
+                () -> checkArgument(false, message));
+
+        assertNull(e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckArgument_false_withMessageSupplier() {
+        final LocalDate today = LocalDate.now();
+        final IllegalArgumentException e = assertThrows(IllegalArgumentException.class,
+                () -> checkArgument(false, () -> "Error message: " + today));
+
+        assertEquals("Error message: " + today, e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckArgument_false_withNullMessageSupplier() {
+        Supplier<String> messageSupplier = null;
+        assertThrows(NullPointerException.class,
+                () -> checkArgument(false, messageSupplier));
+    }
+
+    @Test
+    void testCheckArgument_false_withMessageFormat() {
+        LocalDate today = LocalDate.now();
+        final IllegalArgumentException e = assertThrows(IllegalArgumentException.class,
+                () -> checkArgument(false, "String format: %s", today));
+        assertEquals(String.format("String format: %s", today), e.getMessage());
+    }
+
+    @Test
+    void testCheckArgument_false_withNullMessageFormat() {
+        LocalDate today = LocalDate.now();
+        assertThrows(NullPointerException.class,
+                () -> checkArgument(false, null, today));
+    }
+
+    // #endregion - Argument
+
+    // #region - ArgumentNotNull
+
+    @Test
+    void testCheckArgumentNotNull_notNull() {
+        final Object object = new Object();
+        assertEquals(object, checkArgumentNotNull(object));
+    }
+
+    @Test
+    void testCheckArgumentNotNull_notNull_withMessage() {
+        final Object object = new Object();
+        final String IGNORE_ME = "IGNORE_ME"; // NOSONAR
+        assertEquals(object, checkArgumentNotNull(object, IGNORE_ME));
+    }
+
+    @Test
+    void testCheckArgumentNotNull_notNull_withNullMessage() {
+        final Object object = new Object();
+        final String IGNORE_ME = null; // NOSONAR
+        assertEquals(object, checkArgumentNotNull(object, IGNORE_ME));
+    }
+
+    @Test
+    void testCheckArgumentNotNull_notNull_withMessageSupplier() {
+        final Object object = new Object();
+        assertEquals(object, checkArgumentNotNull(object, () -> "Error message: " + LocalDate.now()));
+    }
+
+    @Test
+    void testCheckArgumentNotNull_notNull_withNullMessageSupplier() {
+        final Object object = new Object();
+        final Supplier<String> IGNORE_ME = null; // NOSONAR
+        assertEquals(object, checkArgumentNotNull(object, IGNORE_ME));
+    }
+
+    @Test
+    void testCheckArgumentNotNull_notNull_withMessageFormat() {
+        final Object object = new Object();
+        LocalDate today = LocalDate.now();
+        assertEquals(object, checkArgumentNotNull(object, "String format: %s", today));
+    }
+
+    @Test
+    void testCheckArgumentNotNull_notNull_withNullMessageFormat() {
+        final Object object = new Object();
+        assertEquals(object, checkArgumentNotNull(object, null, LocalDate.now()));
+    }
+
+    @Test
+    void testCheckArgumentNotNull_null() {
+        final Object object = null;
+        final IllegalArgumentException e = assertThrows(IllegalArgumentException.class,
+                () -> checkArgumentNotNull(object));
+
+        assertNull(e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckArgumentNotNull_null_withMessage() {
+        final Object object = null;
+        final String message = "testCheckArgumentNotNull_null_withMessage";
+
+        final IllegalArgumentException e = assertThrows(IllegalArgumentException.class,
+                () -> checkArgumentNotNull(object, message));
+
+        assertEquals(message, e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckArgumentNotNull_null_withNullMessage() {
+        final Object object = null;
+        final String message = null;
+
+        final IllegalArgumentException e = assertThrows(IllegalArgumentException.class,
+                () -> checkArgumentNotNull(object, message));
+
+        assertNull(e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckArgumentNotNull_null_withMessageSupplier() {
+        final Object object = null;
+        final LocalDate today = LocalDate.now();
+        final IllegalArgumentException e = assertThrows(IllegalArgumentException.class,
+                () -> checkArgumentNotNull(object, () -> "Error message: " + today));
+
+        assertEquals("Error message: " + today, e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckArgumentNotNull_null_withNullMessageSupplier() {
+        final Object object = null;
+        Supplier<String> messageSupplier = null;
+        assertThrows(NullPointerException.class,
+                () -> checkArgumentNotNull(object, messageSupplier));
+    }
+
+    @Test
+    void testCheckArgumentNotNull_null_withMessageFormat() {
+        final Object object = null;
+        LocalDate today = LocalDate.now();
+        final IllegalArgumentException e = assertThrows(IllegalArgumentException.class,
+                () -> checkArgumentNotNull(object, "String format: %s", today));
+        assertEquals(String.format("String format: %s", today), e.getMessage());
+    }
+
+    @Test
+    void testCheckArgumentNotNull_null_withNullMessageFormat() {
+        final Object object = null;
+        LocalDate today = LocalDate.now();
+        assertThrows(NullPointerException.class,
+                () -> checkArgumentNotNull(object, null, today));
+    }
+
+    // #endregion - ArgumentNotNull
+
+    // #region - State
+
+    @Test
+    void testCheckState_true() {
+        checkState(true);
+    }
+
+    @Test
+    void testCheckState_true_withMessage() {
+        final String IGNORE_ME = "IGNORE_ME"; // NOSONAR
+        checkState(true, IGNORE_ME);
+    }
+
+    @Test
+    void testCheckState_true_withNullMessage() {
+        final String IGNORE_ME = null; // NOSONAR
+        checkState(true, IGNORE_ME);
+    }
+
+    @Test
+    void testCheckState_true_withMessageSupplier() {
+        checkState(true, () -> "Error message: " + LocalDate.now());
+    }
+
+    @Test
+    void testCheckState_true_withNullMessageSupplier() {
+        final Supplier<String> IGNORE_ME = null; // NOSONAR
+        checkState(true, IGNORE_ME);
+    }
+
+    @Test
+    void testCheckState_true_withMessageFormat() {
+        LocalDate today = LocalDate.now();
+        checkState(true, "String format: %s", today);
+    }
+
+    @Test
+    void testCheckState_true_withNullMessageFormat() {
+        checkState(true, null, LocalDate.now());
+    }
+
+    @Test
+    void testCheckState_false() {
+        final IllegalStateException e = assertThrows(IllegalStateException.class,
+                () -> checkState(false));
+
+        assertNull(e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckState_false_withMessage() {
+        final String message = "testCheckState_false_withMessage";
+
+        final IllegalStateException e = assertThrows(IllegalStateException.class,
+                () -> checkState(false, message));
+
+        assertEquals(message, e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckState_false_withNullMessage() {
+        final String message = null;
+
+        final IllegalStateException e = assertThrows(IllegalStateException.class,
+                () -> checkState(false, message));
+
+        assertNull(e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckState_false_withMessageSupplier() {
+        final LocalDate today = LocalDate.now();
+        final IllegalStateException e = assertThrows(IllegalStateException.class,
+                () -> checkState(false, () -> "Error message: " + today));
+
+        assertEquals("Error message: " + today, e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckState_false_withNullMessageSupplier() {
+        Supplier<String> messageSupplier = null;
+        assertThrows(NullPointerException.class,
+                () -> checkState(false, messageSupplier));
+    }
+
+    @Test
+    void testCheckState_false_withMessageFormat() {
+        LocalDate today = LocalDate.now();
+        final IllegalStateException e = assertThrows(IllegalStateException.class,
+                () -> checkState(false, "String format: %s", today));
+        assertEquals(String.format("String format: %s", today), e.getMessage());
+    }
+
+    @Test
+    void testCheckState_false_withNullMessageFormat() {
+        LocalDate today = LocalDate.now();
+        assertThrows(NullPointerException.class,
+                () -> checkState(false, null, today));
+    }
+
+    // #endregion - State
+
+    // #region - NotNull
+
+    @Test
+    void testCheckNotNull_notNull() {
+        final Object object = new Object();
+        checkNotNull(object);
+    }
+
+    @Test
+    void testCheckNotNull_notNull_withMessage() {
+        final Object object = new Object();
+        final String IGNORE_ME = "IGNORE_ME"; // NOSONAR
+        checkNotNull(object, IGNORE_ME);
+    }
+
+    @Test
+    void testCheckNotNull_notNull_withNullMessage() {
+        final Object object = new Object();
+        final String IGNORE_ME = null; // NOSONAR
+        checkNotNull(object, IGNORE_ME);
+    }
+
+    @Test
+    void testCheckNotNull_notNull_withMessageSupplier() {
+        final Object object = new Object();
+        checkNotNull(object, () -> "Error message: " + LocalDate.now());
+    }
+
+    @Test
+    void testCheckNotNull_notNull_withNullMessageSupplier() {
+        final Object object = new Object();
+        final Supplier<String> IGNORE_ME = null; // NOSONAR
+        checkNotNull(object, IGNORE_ME);
+    }
+
+    @Test
+    void testCheckNotNull_notNull_withMessageFormat() {
+        final Object object = new Object();
+        LocalDate today = LocalDate.now();
+        checkNotNull(object, "String format: %s", today);
+    }
+
+    @Test
+    void testCheckNotNull_notNull_withNullMessageFormat() {
+        final Object object = new Object();
+        checkNotNull(object, null, LocalDate.now());
+    }
+
+    @Test
+    void testCheckNotNull_null() {
+        final Object object = null;
+        final NullPointerException e = assertThrows(NullPointerException.class,
+                () -> checkNotNull(object));
+
+        assertNull(e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckNotNull_null_withMessage() {
+        final Object object = null;
+        final String message = "testCheckNotNull_null_withMessage";
+
+        final NullPointerException e = assertThrows(NullPointerException.class,
+                () -> checkNotNull(object, message));
+
+        assertEquals(message, e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckNotNull_null_withNullMessage() {
+        final Object object = null;
+        final String message = null;
+
+        final NullPointerException e = assertThrows(NullPointerException.class,
+                () -> checkNotNull(object, message));
+
+        assertNull(e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckNotNull_null_withMessageSupplier() {
+        final Object object = null;
+        final LocalDate today = LocalDate.now();
+        final NullPointerException e = assertThrows(NullPointerException.class,
+                () -> checkNotNull(object, () -> "Error message: " + today));
+
+        assertEquals("Error message: " + today, e.getMessage());
+        assertNull(e.getCause());
+    }
+
+    @Test
+    void testCheckNotNull_null_withNullMessageSupplier() {
+        final Object object = null;
+        Supplier<String> messageSupplier = null;
+        assertThrows(NullPointerException.class,
+                () -> checkNotNull(object, messageSupplier));
+    }
+
+    @Test
+    void testCheckNotNull_null_withMessageFormat() {
+        final Object object = null;
+        LocalDate today = LocalDate.now();
+        final NullPointerException e = assertThrows(NullPointerException.class,
+                () -> checkNotNull(object, "String format: %s", today));
+        assertEquals(String.format("String format: %s", today), e.getMessage());
+    }
+
+    @Test
+    void testCheckNotNull_null_withNullMessageFormat() {
+        final Object object = null;
+        LocalDate today = LocalDate.now();
+        assertThrows(NullPointerException.class,
+                () -> checkNotNull(object, null, today));
+    }
+
+    // #endregion - NotNull
+
+    // #region - Condition
+
+    static final class MyException extends RuntimeException {}
+
+    @Test
+    void testCheckCondition() {
+
+        checkCondition(true, MyException::new);
+
+        final MyException me = new MyException();
+        MyException e = assertThrows(MyException.class, () -> checkCondition(false, () -> me));
+        assertEquals(me, e);
+    }
+
+    // #endregion - Condition
+
+    // ================================
+    // #region - invoke constructor
+    // ================================
+
+    @Test
+    void test_constructor_isNotAccessible_ThrowsIllegalStateException() {
+        Constructor<?>[] constructors = AssertTools.class.getDeclaredConstructors();
+        Arrays.stream(constructors)
+                .forEach(constructor -> {
+                    assertFalse(constructor.isAccessible());
+                    constructor.setAccessible(true);
+                    Throwable cause = assertThrows(Exception.class, constructor::newInstance)
+                            .getCause();
+                    assertInstanceOf(IllegalStateException.class, cause);
+                    assertEquals("Utility class", cause.getMessage());
+                });
+    }
+
+    // ================================
+    // #endregion - invoke constructor
+    // ================================
+}