diff --git a/src/main/java/xyz/zhouxy/plusone/commons/collection/package-info.java b/src/main/java/xyz/zhouxy/plusone/commons/collection/package-info.java
index 4467e60..5bfdc39 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/collection/package-info.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/collection/package-info.java
@@ -24,4 +24,7 @@
  *
  * @author <a href="http://zhouxy.xyz:3000/ZhouXY108">ZhouXY</a>
  */
+@ParametersAreNonnullByDefault
 package xyz.zhouxy.plusone.commons.collection;
+
+import javax.annotation.ParametersAreNonnullByDefault;
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/time/YearQuarter.java b/src/main/java/xyz/zhouxy/plusone/commons/time/YearQuarter.java
index dfaf3c6..c7a4f3c 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/time/YearQuarter.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/time/YearQuarter.java
@@ -27,7 +27,7 @@ import java.util.Calendar;
 import java.util.Date;
 import java.util.Objects;
 
-import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 
 import com.google.errorprone.annotations.Immutable;
 
@@ -52,7 +52,7 @@ public final class YearQuarter implements Comparable<YearQuarter>, Serializable
     /** 季度结束日期 */
     private final LocalDate lastDate;
 
-    private YearQuarter(int year, @Nonnull Quarter quarter) {
+    private YearQuarter(int year, Quarter quarter) {
         this.year = year;
         this.quarter = quarter;
         this.firstDate = quarter.firstMonthDay().atYear(year);
@@ -249,7 +249,7 @@ public final class YearQuarter implements Comparable<YearQuarter>, Serializable
     }
 
     @Override
-    public boolean equals(Object obj) {
+    public boolean equals(@Nullable Object obj) {
         if (this == obj)
             return true;
         if (obj == null)
@@ -264,6 +264,7 @@ public final class YearQuarter implements Comparable<YearQuarter>, Serializable
 
     // #region - compare
 
+    @SuppressWarnings("null")
     @Override
     public int compareTo(YearQuarter other) {
         int cmp = (this.year - other.year);
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/time/package-info.java b/src/main/java/xyz/zhouxy/plusone/commons/time/package-info.java
index 600b2a0..78358d4 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/time/package-info.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/time/package-info.java
@@ -24,4 +24,7 @@
  *
  * @author <a href="http://zhouxy.xyz:3000/ZhouXY108">ZhouXY</a>
  */
+@ParametersAreNonnullByDefault
 package xyz.zhouxy.plusone.commons.time;
+
+import javax.annotation.ParametersAreNonnullByDefault;
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/ArrayTools.java b/src/main/java/xyz/zhouxy/plusone/commons/util/ArrayTools.java
index 8ad67ee..023454e 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/ArrayTools.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/ArrayTools.java
@@ -26,7 +26,6 @@ import java.util.Objects;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
 
-import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
 /**
@@ -259,7 +258,7 @@ public class ArrayTools {
      *
      * @throws IllegalArgumentException 当参数为空时抛出
      */
-    public static <T> boolean isAllElementsNotNull(@Nonnull final T[] arr) {
+    public static <T> boolean isAllElementsNotNull(final T[] arr) {
         AssertTools.checkArgument(arr != null, "The array cannot be null.");
         return Arrays.stream(arr).allMatch(Objects::nonNull);
     }
@@ -622,15 +621,15 @@ public class ArrayTools {
 
     // fill - char
 
-    public static void fill(char[] a, char[] values) {
+    public static void fill(char[] a, @Nullable char[] values) {
         fill(a, 0, a.length, values);
     }
 
-    public static void fill(char[] a, String values) {
+    public static void fill(char[] a, @Nullable String values) {
         fill(a, 0, a.length, values != null ? values.toCharArray() : EMPTY_CHAR_ARRAY);
     }
 
-    public static void fill(char[] a, int fromIndex, int toIndex, char[] values) {
+    public static void fill(char[] a, int fromIndex, int toIndex, @Nullable char[] values) {
         AssertTools.checkArgument(Objects.nonNull(a));
         if (values == null || values.length == 0) {
             return;
@@ -655,11 +654,11 @@ public class ArrayTools {
 
     // fill - byte
 
-    public static void fill(byte[] a, byte[] values) {
+    public static void fill(byte[] a, @Nullable byte[] values) {
         fill(a, 0, a.length, values);
     }
 
-    public static void fill(byte[] a, int fromIndex, int toIndex, byte[] values) {
+    public static void fill(byte[] a, int fromIndex, int toIndex, @Nullable byte[] values) {
         AssertTools.checkArgument(Objects.nonNull(a));
         if (values == null || values.length == 0) {
             return;
@@ -684,11 +683,11 @@ public class ArrayTools {
 
     // fill - short
 
-    public static void fill(short[] a, short[] values) {
+    public static void fill(short[] a, @Nullable short[] values) {
         fill(a, 0, a.length, values);
     }
 
-    public static void fill(short[] a, int fromIndex, int toIndex, short[] values) {
+    public static void fill(short[] a, int fromIndex, int toIndex, @Nullable short[] values) {
         AssertTools.checkArgument(Objects.nonNull(a));
         if (values == null || values.length == 0) {
             return;
@@ -713,11 +712,11 @@ public class ArrayTools {
 
     // fill - int
 
-    public static void fill(int[] a, int[] values) {
+    public static void fill(int[] a, @Nullable int[] values) {
         fill(a, 0, a.length, values);
     }
 
-    public static void fill(int[] a, int fromIndex, int toIndex, int[] values) {
+    public static void fill(int[] a, int fromIndex, int toIndex, @Nullable int[] values) {
         AssertTools.checkArgument(Objects.nonNull(a));
         if (values == null || values.length == 0) {
             return;
@@ -742,11 +741,11 @@ public class ArrayTools {
 
     // fill - long
 
-    public static void fill(long[] a, long[] values) {
+    public static void fill(long[] a, @Nullable long[] values) {
         fill(a, 0, a.length, values);
     }
 
-    public static void fill(long[] a, int fromIndex, int toIndex, long[] values) {
+    public static void fill(long[] a, int fromIndex, int toIndex, @Nullable long[] values) {
         AssertTools.checkArgument(Objects.nonNull(a));
         if (values == null || values.length == 0) {
             return;
@@ -771,11 +770,11 @@ public class ArrayTools {
 
     // fill - float
 
-    public static void fill(float[] a, float[] values) {
+    public static void fill(float[] a, @Nullable float[] values) {
         fill(a, 0, a.length, values);
     }
 
-    public static void fill(float[] a, int fromIndex, int toIndex, float[] values) {
+    public static void fill(float[] a, int fromIndex, int toIndex, @Nullable float[] values) {
         AssertTools.checkArgument(Objects.nonNull(a));
         if (values == null || values.length == 0) {
             return;
@@ -800,11 +799,11 @@ public class ArrayTools {
 
     // fill - double
 
-    public static void fill(double[] a, double[] values) {
+    public static void fill(double[] a, @Nullable double[] values) {
         fill(a, 0, a.length, values);
     }
 
-    public static void fill(double[] a, int fromIndex, int toIndex, double[] values) {
+    public static void fill(double[] a, int fromIndex, int toIndex, @Nullable double[] values) {
         AssertTools.checkArgument(Objects.nonNull(a));
         if (values == null || values.length == 0) {
             return;
@@ -829,15 +828,15 @@ public class ArrayTools {
 
     // fill - T
 
-    public static <T> void fill(@Nonnull T[] a, T[] values) {
+    public static <T> void fill(T[] a, @Nullable T[] values) {
         fillInternal(a, 0, a.length, values);
     }
 
-    public static <T> void fill(@Nonnull T[] a, int fromIndex, int toIndex, T[] values) {
+    public static <T> void fill(T[] a, int fromIndex, int toIndex, @Nullable T[] values) {
         fillInternal(a, fromIndex, toIndex, values);
     }
 
-    private static <T> void fillInternal(@Nonnull T[] a, int fromIndex, int toIndex, @Nullable T[] values) {
+    private static <T> void fillInternal(T[] a, int fromIndex, int toIndex, @Nullable T[] values) {
         AssertTools.checkArgument(Objects.nonNull(a));
         if (values == null || values.length == 0) {
             return;
@@ -864,9 +863,9 @@ public class ArrayTools {
 
     // #region - indexOf
 
-    public static <T> int indexOfWithPredicate(T[] arr, Predicate<? super T> predicate) {
+    public static <T> int indexOfWithPredicate(@Nullable T[] arr, Predicate<? super T> predicate) {
         AssertTools.checkNotNull(predicate);
-        if (isNullOrEmpty(arr)) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = 0; i < arr.length; i++) {
@@ -877,12 +876,12 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static <T> int indexOf(T[] arr, T obj) {
+    public static <T> int indexOf(@Nullable T[] arr, @Nullable T obj) {
         return indexOfWithPredicate(arr, item -> Objects.equals(item, obj));
     }
 
-    public static int indexOf(char[] arr, char value) {
-        if (isNullOrEmpty(arr)) {
+    public static int indexOf(@Nullable char[] arr, char value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = 0; i < arr.length; i++) {
@@ -893,8 +892,8 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static int indexOf(byte[] arr, byte value) {
-        if (isNullOrEmpty(arr)) {
+    public static int indexOf(@Nullable byte[] arr, byte value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = 0; i < arr.length; i++) {
@@ -905,8 +904,8 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static int indexOf(short[] arr, short value) {
-        if (isNullOrEmpty(arr)) {
+    public static int indexOf(@Nullable short[] arr, short value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = 0; i < arr.length; i++) {
@@ -917,8 +916,8 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static int indexOf(int[] arr, int value) {
-        if (isNullOrEmpty(arr)) {
+    public static int indexOf(@Nullable int[] arr, int value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = 0; i < arr.length; i++) {
@@ -929,8 +928,8 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static int indexOf(long[] arr, long value) {
-        if (isNullOrEmpty(arr)) {
+    public static int indexOf(@Nullable long[] arr, long value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = 0; i < arr.length; i++) {
@@ -941,8 +940,8 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static int indexOf(float[] arr, float value) {
-        if (isNullOrEmpty(arr)) {
+    public static int indexOf(@Nullable float[] arr, float value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = 0; i < arr.length; i++) {
@@ -953,8 +952,8 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static int indexOf(double[] arr, double value) {
-        if (isNullOrEmpty(arr)) {
+    public static int indexOf(@Nullable double[] arr, double value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = 0; i < arr.length; i++) {
@@ -969,9 +968,9 @@ public class ArrayTools {
 
     // #region - lastIndexOf
 
-    public static <T> int lastIndexOfWithPredicate(T[] arr, @Nonnull Predicate<? super T> predicate) {
+    public static <T> int lastIndexOfWithPredicate(@Nullable T[] arr, Predicate<? super T> predicate) {
         AssertTools.checkNotNull(predicate);
-        if (isNullOrEmpty(arr)) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = arr.length - 1; i >= 0; i--) {
@@ -986,8 +985,8 @@ public class ArrayTools {
         return lastIndexOfWithPredicate(arr, item -> Objects.equals(item, obj));
     }
 
-    public static int lastIndexOf(char[] arr, char value) {
-        if (isNullOrEmpty(arr)) {
+    public static int lastIndexOf(@Nullable char[] arr, char value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = arr.length - 1; i >= 0; i--) {
@@ -998,8 +997,8 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static int lastIndexOf(byte[] arr, byte value) {
-        if (isNullOrEmpty(arr)) {
+    public static int lastIndexOf(@Nullable byte[] arr, byte value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = arr.length - 1; i >= 0; i--) {
@@ -1010,8 +1009,8 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static int lastIndexOf(short[] arr, short value) {
-        if (isNullOrEmpty(arr)) {
+    public static int lastIndexOf(@Nullable short[] arr, short value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = arr.length - 1; i >= 0; i--) {
@@ -1022,8 +1021,8 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static int lastIndexOf(int[] arr, int value) {
-        if (isNullOrEmpty(arr)) {
+    public static int lastIndexOf(@Nullable int[] arr, int value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = arr.length - 1; i >= 0; i--) {
@@ -1034,8 +1033,8 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static int lastIndexOf(long[] arr, long value) {
-        if (isNullOrEmpty(arr)) {
+    public static int lastIndexOf(@Nullable long[] arr, long value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = arr.length - 1; i >= 0; i--) {
@@ -1046,8 +1045,8 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static int lastIndexOf(float[] arr, float value) {
-        if (isNullOrEmpty(arr)) {
+    public static int lastIndexOf(@Nullable float[] arr, float value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = arr.length - 1; i >= 0; i--) {
@@ -1058,8 +1057,8 @@ public class ArrayTools {
         return NOT_FOUND_INDEX;
     }
 
-    public static int lastIndexOf(double[] arr, double value) {
-        if (isNullOrEmpty(arr)) {
+    public static int lastIndexOf(@Nullable double[] arr, double value) {
+        if (arr == null || arr.length == 0) {
             return NOT_FOUND_INDEX;
         }
         for (int i = arr.length - 1; i >= 0; i--) {
@@ -1074,39 +1073,39 @@ public class ArrayTools {
 
     // #region - contains
 
-    public static <T> boolean contains(T[] arr, T obj) {
+    public static <T> boolean contains(@Nullable T[] arr, @Nullable T obj) {
         return indexOf(arr, obj) > NOT_FOUND_INDEX;
     }
 
-    public static boolean contains(char[] arr, char obj) {
+    public static boolean contains(@Nullable char[] arr, char obj) {
         return indexOf(arr, obj) > NOT_FOUND_INDEX;
     }
 
-    public static boolean contains(byte[] arr, byte obj) {
+    public static boolean contains(@Nullable byte[] arr, byte obj) {
         return indexOf(arr, obj) > NOT_FOUND_INDEX;
     }
 
-    public static boolean contains(short[] arr, short obj) {
+    public static boolean contains(@Nullable short[] arr, short obj) {
         return indexOf(arr, obj) > NOT_FOUND_INDEX;
     }
 
-    public static boolean contains(int[] arr, int obj) {
+    public static boolean contains(@Nullable int[] arr, int obj) {
         return indexOf(arr, obj) > NOT_FOUND_INDEX;
     }
 
-    public static boolean contains(long[] arr, long obj) {
+    public static boolean contains(@Nullable long[] arr, long obj) {
         return indexOf(arr, obj) > NOT_FOUND_INDEX;
     }
 
-    public static boolean contains(float[] arr, float obj) {
+    public static boolean contains(@Nullable float[] arr, float obj) {
         return indexOf(arr, obj) > NOT_FOUND_INDEX;
     }
 
-    public static boolean contains(double[] arr, double obj) {
+    public static boolean contains(@Nullable double[] arr, double obj) {
         return indexOf(arr, obj) > NOT_FOUND_INDEX;
     }
 
-    public static boolean containsValue(BigDecimal[] arr, BigDecimal obj) {
+    public static boolean containsValue(@Nullable BigDecimal[] arr, @Nullable BigDecimal obj) {
         return indexOfWithPredicate(arr, item -> BigDecimals.equalsValue(item, obj)) > NOT_FOUND_INDEX;
     }
 
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/AssertTools.java b/src/main/java/xyz/zhouxy/plusone/commons/util/AssertTools.java
index cf31308..55aae40 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/AssertTools.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/AssertTools.java
@@ -20,7 +20,7 @@ import java.util.Objects;
 import java.util.Optional;
 import java.util.function.Supplier;
 
-import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 
 import xyz.zhouxy.plusone.commons.exception.DataNotExistsException;
 import xyz.zhouxy.plusone.commons.exception.system.DataOperationResultException;
@@ -55,12 +55,12 @@ public class AssertTools {
     }
 
     /** Throw {@link IllegalArgumentException} if the {@code condition} is false. */
-    public static void checkArgument(boolean condition, String errMsg) {
+    public static void checkArgument(boolean condition, @Nullable String errMsg) {
         checkCondition(condition, () -> new IllegalArgumentException(errMsg));
     }
 
     /** Throw {@link IllegalArgumentException} if the {@code condition} is false. */
-    public static void checkArgument(boolean condition, @Nonnull Supplier<String> messageSupplier) {
+    public static void checkArgument(boolean condition, Supplier<String> messageSupplier) {
         checkCondition(condition, () -> new IllegalArgumentException(messageSupplier.get()));
     }
 
@@ -83,12 +83,12 @@ public class AssertTools {
     }
 
     /** Throw {@link IllegalStateException} if the {@code condition} is false. */
-    public static void checkState(boolean condition, String errMsg) {
+    public static void checkState(boolean condition, @Nullable String errMsg) {
         checkCondition(condition, () -> new IllegalStateException(errMsg));
     }
 
     /** Throw {@link IllegalStateException} if the {@code condition} is false. */
-    public static void checkState(boolean condition, @Nonnull Supplier<String> messageSupplier) {
+    public static void checkState(boolean condition, Supplier<String> messageSupplier) {
         checkCondition(condition, () -> new IllegalStateException(messageSupplier.get()));
     }
 
@@ -106,22 +106,22 @@ public class AssertTools {
     // ================================
 
     /** Throw {@link NullPointerException} if the {@code obj} is null. */
-    public static <T> void checkNotNull(T obj) {
+    public static <T> void checkNotNull(@Nullable T obj) {
         checkCondition(obj != null, NullPointerException::new);
     }
 
     /** Throw {@link NullPointerException} if the {@code obj} is null. */
-    public static <T> void checkNotNull(T obj, String errMsg) {
+    public static <T> void checkNotNull(@Nullable T obj, String errMsg) {
         checkCondition(obj != null, () -> new NullPointerException(errMsg));
     }
 
     /** Throw {@link NullPointerException} if the {@code obj} is null. */
-    public static <T> void checkNotNull(T obj, @Nonnull Supplier<String> messageSupplier) {
+    public static <T> void checkNotNull(@Nullable T obj, Supplier<String> messageSupplier) {
         checkCondition(obj != null, () -> new NullPointerException(messageSupplier.get()));
     }
 
     /** Throw {@link NullPointerException} if the {@code obj} is null. */
-    public static <T> void checkNotNull(T obj, String format, Object... args) {
+    public static <T> void checkNotNull(@Nullable T obj, String format, Object... args) {
         checkCondition(obj != null, () -> new NullPointerException(String.format(format, args)));
     }
 
@@ -134,56 +134,56 @@ public class AssertTools {
     // ================================
 
     /** Throw {@link DataNotExistsException} if the {@code obj} is null. */
-    public static <T> T checkExists(T obj)
+    public static <T> T checkExists(@Nullable T obj)
             throws DataNotExistsException {
         checkCondition(Objects.nonNull(obj), DataNotExistsException::new);
         return obj;
     }
 
     /** Throw {@link DataNotExistsException} if the {@code obj} is null. */
-    public static <T> T checkExists(T obj, String message)
+    public static <T> T checkExists(@Nullable T obj, String message)
             throws DataNotExistsException {
         checkCondition(Objects.nonNull(obj), () -> new DataNotExistsException(message));
         return obj;
     }
 
     /** Throw {@link DataNotExistsException} if the {@code obj} is null. */
-    public static <T> T checkExists(T obj, @Nonnull Supplier<String> messageSupplier)
+    public static <T> T checkExists(@Nullable T obj, Supplier<String> messageSupplier)
             throws DataNotExistsException {
         checkCondition(Objects.nonNull(obj), () -> new DataNotExistsException(messageSupplier.get()));
         return obj;
     }
 
     /** Throw {@link DataNotExistsException} if the {@code obj} is null. */
-    public static <T> T checkExists(T obj, String format, Object... args)
+    public static <T> T checkExists(@Nullable T obj, String format, Object... args)
             throws DataNotExistsException {
         checkCondition(Objects.nonNull(obj), () -> new DataNotExistsException(String.format(format, args)));
         return obj;
     }
 
     /** Throw {@link DataNotExistsException} if the {@code optional} is present. */
-    public static <T> T checkExists(@Nonnull Optional<T> optional)
+    public static <T> T checkExists(Optional<T> optional)
             throws DataNotExistsException {
         checkCondition(optional.isPresent(), DataNotExistsException::new);
         return optional.get();
     }
 
     /** Throw {@link DataNotExistsException} if the {@code optional} is present. */
-    public static <T> T checkExists(@Nonnull Optional<T> optional, String message)
+    public static <T> T checkExists(Optional<T> optional, String message)
             throws DataNotExistsException {
         checkCondition(optional.isPresent(), () -> new DataNotExistsException(message));
         return optional.get();
     }
 
     /** Throw {@link DataNotExistsException} if the {@code optional} is present. */
-    public static <T> T checkExists(@Nonnull Optional<T> optional, @Nonnull Supplier<String> messageSupplier)
+    public static <T> T checkExists(Optional<T> optional, Supplier<String> messageSupplier)
             throws DataNotExistsException {
         checkCondition(optional.isPresent(), () -> new DataNotExistsException(messageSupplier.get()));
         return optional.get();
     }
 
     /** Throw {@link DataNotExistsException} if the {@code optional} is present. */
-    public static <T> T checkExists(@Nonnull Optional<T> optional, String format, Object... args)
+    public static <T> T checkExists(Optional<T> optional, String format, Object... args)
             throws DataNotExistsException {
         checkCondition(optional.isPresent(), () -> new DataNotExistsException(String.format(format, args)));
         return optional.get();
@@ -202,17 +202,18 @@ public class AssertTools {
                 "The number of rows affected is expected to be %d, but is: %d", expectedValue, result);
     }
 
-    public static void checkAffectedRows(int expectedValue, int result, String message) {
+    public static void checkAffectedRows(int expectedValue, int result, @Nullable String message) {
         checkCondition(expectedValue == result, () -> new DataOperationResultException(message));
     }
 
     public static void checkAffectedRows(int expectedValue, int result,
-            @Nonnull Supplier<String> messageSupplier) {
+            Supplier<String> messageSupplier) {
         checkCondition(expectedValue == result,
                 () -> new DataOperationResultException(messageSupplier.get()));
     }
 
-    public static void checkAffectedRows(int expectedValue, int result, String format, Object... args) {
+    public static void checkAffectedRows(int expectedValue, int result,
+            String format, Object... args) {
         checkCondition(expectedValue == result,
                 () -> new DataOperationResultException(String.format(format, args)));
     }
@@ -222,17 +223,18 @@ public class AssertTools {
                 "The number of rows affected is expected to be %d, but is: %d", expectedValue, result);
     }
 
-    public static void checkAffectedRows(long expectedValue, long result, String message) {
+    public static void checkAffectedRows(long expectedValue, long result, @Nullable String message) {
         checkCondition(expectedValue == result, () -> new DataOperationResultException(message));
     }
 
     public static void checkAffectedRows(long expectedValue, long result,
-            @Nonnull Supplier<String> messageSupplier) {
+            Supplier<String> messageSupplier) {
         checkCondition(expectedValue == result,
                 () -> new DataOperationResultException(messageSupplier.get()));
     }
 
-    public static void checkAffectedRows(long expectedValue, long result, String format, Object... args) {
+    public static void checkAffectedRows(long expectedValue, long result,
+            String format, Object... args) {
         checkCondition(expectedValue == result,
                 () -> new DataOperationResultException(String.format(format, args)));
     }
@@ -246,7 +248,7 @@ public class AssertTools {
         checkAffectedRows(1, result, message);
     }
 
-    public static void checkAffectedOneRow(int result, @Nonnull Supplier<String> messageSupplier) {
+    public static void checkAffectedOneRow(int result, Supplier<String> messageSupplier) {
         checkAffectedRows(1, result, messageSupplier);
     }
 
@@ -263,11 +265,12 @@ public class AssertTools {
         checkAffectedRows(1L, result, message);
     }
 
-    public static void checkAffectedOneRow(long result, @Nonnull Supplier<String> messageSupplier) {
+    public static void checkAffectedOneRow(long result, Supplier<String> messageSupplier) {
         checkAffectedRows(1L, result, messageSupplier);
     }
 
-    public static void checkAffectedOneRow(long result, String format, Object... args) {
+    public static void checkAffectedOneRow(long result,
+            String format, Object... args) {
         checkAffectedRows(1L, result, format, args);
     }
 
@@ -279,7 +282,7 @@ public class AssertTools {
     // #region - Condition
     // ================================
 
-    public static <T extends Exception> void checkCondition(boolean condition, @Nonnull Supplier<T> e)
+    public static <T extends Exception> void checkCondition(boolean condition, Supplier<T> e)
             throws T {
         if (!condition) {
             throw e.get();
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/BigDecimals.java b/src/main/java/xyz/zhouxy/plusone/commons/util/BigDecimals.java
index 1b006c7..21ab208 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/BigDecimals.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/BigDecimals.java
@@ -46,7 +46,9 @@ public class BigDecimals {
     }
 
     public static boolean ge(BigDecimal a, BigDecimal b) {
-        return gt(a, b) || equalsValue(a, b);
+        AssertTools.checkNotNull(a, "Parameter could not be null.");
+        AssertTools.checkNotNull(b, "Parameter could not be null.");
+        return (a == b) || (a.compareTo(b) >= 0);
     }
 
     public static boolean lt(BigDecimal a, BigDecimal b) {
@@ -56,7 +58,9 @@ public class BigDecimals {
     }
 
     public static boolean le(BigDecimal a, BigDecimal b) {
-        return lt(a, b) || equalsValue(a, b);
+        AssertTools.checkNotNull(a, "Parameter could not be null.");
+        AssertTools.checkNotNull(b, "Parameter could not be null.");
+        return (a == b) || (a.compareTo(b) <= 0);
     }
 
     public static BigDecimal sum(final BigDecimal... numbers) {
@@ -79,7 +83,7 @@ public class BigDecimals {
     }
 
     @StaticFactoryMethod(BigDecimal.class)
-    public static BigDecimal of(final String val) {
+    public static BigDecimal of(@Nullable final String val) {
         return (StringTools.isNotBlank(val)) ? new BigDecimal(val) : BigDecimal.ZERO;
     }
 
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/EnumTools.java b/src/main/java/xyz/zhouxy/plusone/commons/util/EnumTools.java
index ba1f76a..0283d98 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/EnumTools.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/EnumTools.java
@@ -18,7 +18,6 @@ package xyz.zhouxy.plusone.commons.util;
 
 import java.util.function.Supplier;
 
-import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
 /**
@@ -42,7 +41,7 @@ public final class EnumTools {
      * @deprecated 不推荐使用枚举的 ordinal。
      */
     @Deprecated
-    private static <E extends Enum<?>> E valueOfInternal(@Nonnull Class<E> enumType, int ordinal) { // NOSONAR 该方法弃用，但不删掉
+    private static <E extends Enum<?>> E valueOfInternal(Class<E> enumType, int ordinal) { // NOSONAR 该方法弃用，但不删掉
         E[] values = enumType.getEnumConstants();
         AssertTools.checkCondition((ordinal >= 0 && ordinal < values.length),
                 () -> new EnumConstantNotPresentException(enumType, Integer.toString(ordinal)));
@@ -76,7 +75,7 @@ public final class EnumTools {
      */
     @Deprecated
     public static <E extends Enum<?>> E valueOf(Class<E> enumType, // NOSONAR 该方法弃用，但不删掉
-            @Nullable Integer ordinal, E defaultValue) {
+            @Nullable Integer ordinal, @Nullable E defaultValue) {
         AssertTools.checkNotNull(enumType);
         return null == ordinal ? defaultValue : valueOfInternal(enumType, ordinal);
     }
@@ -190,7 +189,7 @@ public final class EnumTools {
      */
     @Nullable
     private static <E extends Enum<?>> Integer checkOrdinalOrDefaultInternal(
-            @Nonnull Class<E> enumType,
+            Class<E> enumType,
             @Nullable Integer ordinal,
             @Nullable Integer defaultValue) {
         return ordinal != null
@@ -200,9 +199,9 @@ public final class EnumTools {
 
     @Nullable
     private static <E extends Enum<?>> Integer checkOrdinalOrGetInternal(
-            @Nonnull Class<E> enumType,
+            Class<E> enumType,
             @Nullable Integer ordinal,
-            @Nonnull Supplier<Integer> defaultValueSupplier) {
+            Supplier<Integer> defaultValueSupplier) {
         return ordinal != null
                 ? checkOrdinal(enumType, ordinal)
                 : defaultValueSupplier.get();
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/Enumeration.java b/src/main/java/xyz/zhouxy/plusone/commons/util/Enumeration.java
index aee9e0b..1a3b1a6 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/Enumeration.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/Enumeration.java
@@ -24,6 +24,8 @@ import java.util.Objects;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
+import javax.annotation.Nullable;
+
 import xyz.zhouxy.plusone.commons.annotation.StaticFactoryMethod;
 
 /**
@@ -54,6 +56,7 @@ public abstract class Enumeration<T extends Enumeration<T>> // NOSONAR 暂不移
         return name;
     }
 
+    @SuppressWarnings("null")
     @Override
     public final int compareTo(final T o) {
         return Integer.compare(this.id, o.id);
@@ -65,7 +68,7 @@ public abstract class Enumeration<T extends Enumeration<T>> // NOSONAR 暂不移
     }
 
     @Override
-    public final boolean equals(final Object obj) {
+    public final boolean equals(@Nullable final Object obj) {
         if (this == obj)
             return true;
         if (obj == null)
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/IdGenerator.java b/src/main/java/xyz/zhouxy/plusone/commons/util/IdGenerator.java
index cd72ac9..9dc028b 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/IdGenerator.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/IdGenerator.java
@@ -21,8 +21,6 @@ import java.util.Objects;
 import java.util.UUID;
 import java.util.concurrent.ConcurrentHashMap;
 
-import javax.annotation.Nonnull;
-
 /**
  * ID 生成器
  *
@@ -50,7 +48,7 @@ public class IdGenerator {
         return toSimpleString(UUID.randomUUID());
     }
 
-    public static String toSimpleString(@Nonnull UUID uuid) {
+    public static String toSimpleString(UUID uuid) {
         AssertTools.checkArgument(Objects.nonNull(uuid));
         return (uuidDigits(uuid.getMostSignificantBits() >> 32, 8) +
                 uuidDigits(uuid.getMostSignificantBits() >> 16, 4) +
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/IdWorker.java b/src/main/java/xyz/zhouxy/plusone/commons/util/IdWorker.java
index 4d42af6..3155099 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/IdWorker.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/IdWorker.java
@@ -22,6 +22,8 @@ import java.util.Enumeration;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.concurrent.atomic.AtomicLong;
 
+import javax.annotation.Nullable;
+
 import xyz.zhouxy.plusone.commons.exception.system.NoAvailableMacFoundException;
 
 /**
@@ -115,7 +117,7 @@ public class IdWorker {
      * init workerId
      * @param workerId if null, then auto generate one
      */
-    private void initWorkerId(Long workerId) {
+    private void initWorkerId(@Nullable Long workerId) {
         if (workerId == null) {
             workerId = generateWorkerId();
         }
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/RandomTools.java b/src/main/java/xyz/zhouxy/plusone/commons/util/RandomTools.java
index d4b3cef..0100b1a 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/RandomTools.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/RandomTools.java
@@ -22,8 +22,6 @@ import java.util.Objects;
 import java.util.Random;
 import java.util.concurrent.ThreadLocalRandom;
 
-import javax.annotation.Nonnull;
-
 /**
  * 随机工具类
  * <p>
@@ -68,20 +66,20 @@ public final class RandomTools {
      * @param length           字符串长度
      * @return 随机字符串
      */
-    public static String randomStr(@Nonnull Random random, @Nonnull char[] sourceCharacters, int length) {
+    public static String randomStr(Random random, char[] sourceCharacters, int length) {
         AssertTools.checkArgument(Objects.nonNull(random), "Random cannot be null.");
         AssertTools.checkArgument(Objects.nonNull(sourceCharacters), "Source characters cannot be null.");
         AssertTools.checkArgument(length >= 0, "The length should be greater than or equal to zero.");
         return randomStrInternal(random, sourceCharacters, length);
     }
 
-    public static String randomStr(@Nonnull char[] sourceCharacters, int length) {
+    public static String randomStr(char[] sourceCharacters, int length) {
         AssertTools.checkArgument(Objects.nonNull(sourceCharacters), "Source characters cannot be null.");
         AssertTools.checkArgument(length >= 0, "The length should be greater than or equal to zero.");
         return randomStrInternal(ThreadLocalRandom.current(), sourceCharacters, length);
     }
 
-    public static String secureRandomStr(@Nonnull char[] sourceCharacters, int length) {
+    public static String secureRandomStr(char[] sourceCharacters, int length) {
         AssertTools.checkArgument(Objects.nonNull(sourceCharacters), "Source characters cannot be null.");
         AssertTools.checkArgument(length >= 0, "The length should be greater than or equal to zero.");
         return randomStrInternal(DEFAULT_SECURE_RANDOM, sourceCharacters, length);
@@ -97,20 +95,20 @@ public final class RandomTools {
      * @param length           字符串长度
      * @return 随机字符串
      */
-    public static String randomStr(@Nonnull Random random, @Nonnull String sourceCharacters, int length) {
+    public static String randomStr(Random random, String sourceCharacters, int length) {
         AssertTools.checkArgument(Objects.nonNull(random), "Random cannot be null.");
         AssertTools.checkArgument(Objects.nonNull(sourceCharacters), "Source characters cannot be null.");
         AssertTools.checkArgument(length >= 0, "The length should be greater than or equal to zero.");
         return randomStrInternal(random, sourceCharacters, length);
     }
 
-    public static String randomStr(@Nonnull String sourceCharacters, int length) {
+    public static String randomStr(String sourceCharacters, int length) {
         AssertTools.checkArgument(Objects.nonNull(sourceCharacters), "Source characters cannot be null.");
         AssertTools.checkArgument(length >= 0, "The length should be greater than or equal to zero.");
         return randomStrInternal(ThreadLocalRandom.current(), sourceCharacters, length);
     }
 
-    public static String secureRandomStr(@Nonnull String sourceCharacters, int length) {
+    public static String secureRandomStr(String sourceCharacters, int length) {
         AssertTools.checkArgument(Objects.nonNull(sourceCharacters), "Source characters cannot be null.");
         AssertTools.checkArgument(length >= 0, "The length should be greater than or equal to zero.");
         return randomStrInternal(DEFAULT_SECURE_RANDOM, sourceCharacters, length);
@@ -126,7 +124,7 @@ public final class RandomTools {
      * @param length           字符串长度
      * @return 随机字符串
      */
-    private static String randomStrInternal(@Nonnull Random random, @Nonnull char[] sourceCharacters, int length) {
+    private static String randomStrInternal(Random random, char[] sourceCharacters, int length) {
         if (length == 0) {
             return StringTools.EMPTY_STRING;
         }
@@ -147,7 +145,7 @@ public final class RandomTools {
      * @param length           字符串长度
      * @return 随机字符串
      */
-    private static String randomStrInternal(@Nonnull Random random, @Nonnull String sourceCharacters, int length) {
+    private static String randomStrInternal(Random random, String sourceCharacters, int length) {
         if (length == 0) {
             return StringTools.EMPTY_STRING;
         }
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/RegexTools.java b/src/main/java/xyz/zhouxy/plusone/commons/util/RegexTools.java
index 53551f8..564c875 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/RegexTools.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/RegexTools.java
@@ -272,7 +272,7 @@ public final class RegexTools {
      * @return {@link Pattern} 实例
      */
     @Nonnull
-    private static Pattern cacheAndGetPatternInternal(@Nonnull final String pattern) {
+    private static Pattern cacheAndGetPatternInternal(final String pattern) {
         if (PATTERN_CACHE.size() < MAX_CACHE_SIZE) {
             return PATTERN_CACHE.computeIfAbsent(pattern, Pattern::compile);
         }
@@ -290,7 +290,7 @@ public final class RegexTools {
      * @return {@link Pattern} 实例
      */
     @Nonnull
-    private static Pattern getPatternInternal(@Nonnull final String pattern) {
+    private static Pattern getPatternInternal(final String pattern) {
         Pattern result = PATTERN_CACHE.get(pattern);
         if (result == null) {
             result = Pattern.compile(pattern);
@@ -305,7 +305,7 @@ public final class RegexTools {
      * @return {@link Pattern} 实例数组
      */
     @Nonnull
-    private static Pattern[] cacheAndGetPatternsInternal(@Nonnull final String[] patterns) {
+    private static Pattern[] cacheAndGetPatternsInternal(final String[] patterns) {
         return Arrays.stream(patterns)
                 .map(RegexTools::cacheAndGetPatternInternal)
                 .toArray(Pattern[]::new);
@@ -318,7 +318,7 @@ public final class RegexTools {
      * @return {@link Pattern} 实例数组
      */
     @Nonnull
-    private static Pattern[] getPatternsInternal(@Nonnull final String[] patterns) {
+    private static Pattern[] getPatternsInternal(final String[] patterns) {
         return Arrays.stream(patterns)
                 .map(RegexTools::getPatternInternal)
                 .toArray(Pattern[]::new);
@@ -331,17 +331,17 @@ public final class RegexTools {
      * @param pattern 正则
      * @return 判断结果
      */
-    private static boolean matchesInternal(@Nullable final CharSequence input, @Nonnull final Pattern pattern) {
+    private static boolean matchesInternal(@Nullable final CharSequence input, final Pattern pattern) {
         return input != null && pattern.matcher(input).matches();
     }
 
-    private static boolean matchesOneInternal(@Nullable final CharSequence input, @Nonnull final Pattern[] patterns) {
+    private static boolean matchesOneInternal(@Nullable final CharSequence input, final Pattern[] patterns) {
         return input != null
                 && Arrays.stream(patterns)
                         .anyMatch(pattern -> pattern.matcher(input).matches());
     }
 
-    private static boolean matchesAllInternal(@Nullable final CharSequence input, @Nonnull final Pattern[] patterns) {
+    private static boolean matchesAllInternal(@Nullable final CharSequence input, final Pattern[] patterns) {
         return input != null
                 && Arrays.stream(patterns)
                         .allMatch(pattern -> pattern.matcher(input).matches());
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/StringTools.java b/src/main/java/xyz/zhouxy/plusone/commons/util/StringTools.java
index 5dd5659..1a3f189 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/StringTools.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/StringTools.java
@@ -18,14 +18,13 @@ package xyz.zhouxy.plusone.commons.util;
 
 import java.util.Objects;
 
-import com.google.common.annotations.Beta;
+import javax.annotation.Nullable;
 
-@Beta
 public class StringTools {
 
     public static final String EMPTY_STRING = "";
 
-    public static boolean isNotBlank(final String cs) {
+    public static boolean isNotBlank(@Nullable final String cs) {
         if (cs == null || cs.isEmpty()) {
             return false;
         }
@@ -41,7 +40,7 @@ public class StringTools {
         return repeat(str, times, Integer.MAX_VALUE);
     }
 
-    public static String repeat(String str, int times, int maxLength) {
+    public static String repeat(final String str, int times, int maxLength) {
         AssertTools.checkArgument(Objects.nonNull(str));
         return String.valueOf(ArrayTools.repeat(str.toCharArray(), times, maxLength));
     }
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/TreeBuilder.java b/src/main/java/xyz/zhouxy/plusone/commons/util/TreeBuilder.java
index 824d645..b6e28b0 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/TreeBuilder.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/TreeBuilder.java
@@ -45,7 +45,7 @@ public class TreeBuilder<T, TSubTree extends T, TIdentity> {
     }
 
     public TreeBuilder(Function<T, TIdentity> identityGetter, Function<T, Optional<TIdentity>> parentIdentityGetter,
-            BiConsumer<TSubTree, T> addChild, Comparator<? super T> defaultComparator) {
+            BiConsumer<TSubTree, T> addChild, @Nullable Comparator<? super T> defaultComparator) {
         this.identityGetter = identityGetter;
         this.parentIdentityGetter = parentIdentityGetter;
         this.addChildMethod = addChild;
diff --git a/src/main/java/xyz/zhouxy/plusone/commons/util/package-info.java b/src/main/java/xyz/zhouxy/plusone/commons/util/package-info.java
index a5bb28e..ed29202 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/util/package-info.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/util/package-info.java
@@ -22,4 +22,7 @@
  *
  * @author <a href="http://zhouxy.xyz:3000/ZhouXY108">ZhouXY</a>
  */
+@ParametersAreNonnullByDefault
 package xyz.zhouxy.plusone.commons.util;
+
+import javax.annotation.ParametersAreNonnullByDefault;
diff --git a/src/test/java/xyz/zhouxy/plusone/commons/time/YearQuarterTests.java b/src/test/java/xyz/zhouxy/plusone/commons/time/YearQuarterTests.java
index 70e4c7e..9e78e09 100644
--- a/src/test/java/xyz/zhouxy/plusone/commons/time/YearQuarterTests.java
+++ b/src/test/java/xyz/zhouxy/plusone/commons/time/YearQuarterTests.java
@@ -36,6 +36,7 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 @Slf4j
+@SuppressWarnings("null")
 public class YearQuarterTests {
 
     // ================================
@@ -588,7 +589,7 @@ public class YearQuarterTests {
             Year.MIN_VALUE,
             Year.MAX_VALUE,
     })
-    void of_ValidYearMonth_CreatesYearMnoth_Q1(int year) {
+    void of_ValidYearMonth_CreatesYearMonth_Q1(int year) {
         {
             YearMonth yearMonth = YearMonth.of(year, 1);
             YearQuarter yearQuarter = YearQuarter.of(yearMonth);
@@ -619,7 +620,7 @@ public class YearQuarterTests {
             Year.MIN_VALUE,
             Year.MAX_VALUE,
     })
-    void of_ValidYearMonth_CreatesYearMnoth_Q2(int year) {
+    void of_ValidYearMonth_CreatesYearMonth_Q2(int year) {
         {
             YearMonth yearMonth = YearMonth.of(year, 4);
             YearQuarter yearQuarter = YearQuarter.of(yearMonth);
@@ -650,7 +651,7 @@ public class YearQuarterTests {
             Year.MIN_VALUE,
             Year.MAX_VALUE,
     })
-    void of_ValidYearMonth_CreatesYearMnoth_Q3(int year) {
+    void of_ValidYearMonth_CreatesYearMonth_Q3(int year) {
         {
             YearMonth yearMonth = YearMonth.of(year, 7);
             YearQuarter yearQuarter = YearQuarter.of(yearMonth);
@@ -681,7 +682,7 @@ public class YearQuarterTests {
             Year.MIN_VALUE,
             Year.MAX_VALUE,
     })
-    void of_ValidYearMonth_CreatesYearMnoth_Q4(int year) {
+    void of_ValidYearMonth_CreatesYearMonth_Q4(int year) {
         {
             YearMonth yearMonth = YearMonth.of(year, 10);
             YearQuarter yearQuarter = YearQuarter.of(yearMonth);
@@ -712,7 +713,7 @@ public class YearQuarterTests {
             Year.MIN_VALUE,
             Year.MAX_VALUE,
     })
-    void of_NullYearMonth_CreatesYearMnoth_Q4(int year) {
+    void of_NullYearMonth_CreatesYearMonth_Q4(int year) {
         YearMonth yearMonth = null;
         assertThrows(NullPointerException.class,
                 () -> YearQuarter.of(yearMonth));
diff --git a/src/test/java/xyz/zhouxy/plusone/commons/util/BigDecimalsTests.java b/src/test/java/xyz/zhouxy/plusone/commons/util/BigDecimalsTests.java
index 61e2b98..fd632e5 100644
--- a/src/test/java/xyz/zhouxy/plusone/commons/util/BigDecimalsTests.java
+++ b/src/test/java/xyz/zhouxy/plusone/commons/util/BigDecimalsTests.java
@@ -27,6 +27,7 @@ import org.junit.jupiter.api.Test;
 import lombok.extern.slf4j.Slf4j;
 
 @Slf4j
+@SuppressWarnings("null")
 public class BigDecimalsTests {
 
     @Test
diff --git a/src/test/java/xyz/zhouxy/plusone/commons/util/EnumToolsTests.java b/src/test/java/xyz/zhouxy/plusone/commons/util/EnumToolsTests.java
index 9a695af..609570f 100644
--- a/src/test/java/xyz/zhouxy/plusone/commons/util/EnumToolsTests.java
+++ b/src/test/java/xyz/zhouxy/plusone/commons/util/EnumToolsTests.java
@@ -30,7 +30,7 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
 
-@SuppressWarnings("deprecation")
+@SuppressWarnings({"deprecation", "null"})
 public
 class EnumToolsTests {
 
diff --git a/src/test/java/xyz/zhouxy/plusone/commons/util/OptionalToolsTests.java b/src/test/java/xyz/zhouxy/plusone/commons/util/OptionalToolsTests.java
index 6569fca..a4bb0bb 100644
--- a/src/test/java/xyz/zhouxy/plusone/commons/util/OptionalToolsTests.java
+++ b/src/test/java/xyz/zhouxy/plusone/commons/util/OptionalToolsTests.java
@@ -35,6 +35,7 @@ import org.junit.jupiter.api.Test;
 /**
  * {@link OptionalTools} 单元测试
  */
+@SuppressWarnings("null")
 public
 class OptionalToolsTests {
 
diff --git a/src/test/java/xyz/zhouxy/plusone/commons/util/RegexToolsTests.java b/src/test/java/xyz/zhouxy/plusone/commons/util/RegexToolsTests.java
index 7ad974f..b8fef08 100644
--- a/src/test/java/xyz/zhouxy/plusone/commons/util/RegexToolsTests.java
+++ b/src/test/java/xyz/zhouxy/plusone/commons/util/RegexToolsTests.java
@@ -28,6 +28,7 @@ import org.junit.jupiter.api.Test;
 import lombok.extern.slf4j.Slf4j;
 
 @Slf4j
+@SuppressWarnings("null")
 public
 class RegexToolsTests {
 
diff --git a/src/test/java/xyz/zhouxy/plusone/commons/util/StringToolsTests.java b/src/test/java/xyz/zhouxy/plusone/commons/util/StringToolsTests.java
index 94d88a5..341b9b1 100644
--- a/src/test/java/xyz/zhouxy/plusone/commons/util/StringToolsTests.java
+++ b/src/test/java/xyz/zhouxy/plusone/commons/util/StringToolsTests.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 
 import org.junit.jupiter.api.Test;
 
+@SuppressWarnings("null")
 public
 class StringToolsTests {
 
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 cc7c022..6a662ae 100644
--- a/src/test/java/xyz/zhouxy/plusone/commons/util/TreeBuilderTests.java
+++ b/src/test/java/xyz/zhouxy/plusone/commons/util/TreeBuilderTests.java
@@ -39,6 +39,7 @@ import cn.hutool.core.util.ObjectUtil;
 import lombok.EqualsAndHashCode;
 import lombok.ToString;
 
+@SuppressWarnings("null")
 class TreeBuilderTests {
 
     private static final Logger log = LoggerFactory.getLogger(TreeBuilderTests.class);