diff --git a/src/main/java/xyz/zhouxy/plusone/commons/function/Predicates.java b/src/main/java/xyz/zhouxy/plusone/commons/function/Predicates.java
index d0ee32c..b949d18 100644
--- a/src/main/java/xyz/zhouxy/plusone/commons/function/Predicates.java
+++ b/src/main/java/xyz/zhouxy/plusone/commons/function/Predicates.java
@@ -2,9 +2,13 @@ package xyz.zhouxy.plusone.commons.function;
 
 import java.util.function.Predicate;
 
-public class Predicates<T> {
+public class Predicates {
 
-    public final Predicate<T> of(Predicate<? super T> predicate) {
+    public static <T> Predicate<T> of(Predicate<? super T> predicate) {
         return predicate::test;
     }
+
+    private Predicates() {
+        throw new IllegalStateException("Utility class");
+    }
 }
diff --git a/src/test/java/xyz/zhouxy/plusone/commons/function/FunctionTests.java b/src/test/java/xyz/zhouxy/plusone/commons/function/FunctionTests.java
index ddf94b1..1ec1353 100644
--- a/src/test/java/xyz/zhouxy/plusone/commons/function/FunctionTests.java
+++ b/src/test/java/xyz/zhouxy/plusone/commons/function/FunctionTests.java
@@ -1,5 +1,6 @@
 package xyz.zhouxy.plusone.commons.function;
 
+import java.util.Objects;
 import java.util.function.Predicate;
 
 import org.apache.commons.lang3.StringUtils;
@@ -11,12 +12,8 @@ class FunctionTests {
     @Test
     void test() {
         String str = "";
-        Predicate<String> predicate = new Predicates<String>().of(this::nonNull)
-                .or(StringUtils::isNotBlank);
-        Assert.isTrue(predicate.test(str), "未通过");
-    }
-
-    boolean nonNull(Object obj) {
-        return obj != null;
+        Predicate<String> predicate = Predicates.<String>of(Objects::nonNull)
+                .and(StringUtils::isNotEmpty);
+        Assert.isFalse(predicate.test(str), "校验应是不通过");
     }
 }