diff --git a/core-java-modules/core-java-lang-oop-types/src/main/java/com/baeldung/primitivetype/PrimitiveTypeUtil.java b/core-java-modules/core-java-lang-oop-types/src/main/java/com/baeldung/primitivetype/PrimitiveTypeUtil.java
index 9607a0008f..ff70da1839 100644
--- a/core-java-modules/core-java-lang-oop-types/src/main/java/com/baeldung/primitivetype/PrimitiveTypeUtil.java
+++ b/core-java-modules/core-java-lang-oop-types/src/main/java/com/baeldung/primitivetype/PrimitiveTypeUtil.java
@@ -19,8 +19,8 @@ public class PrimitiveTypeUtil {
         WRAPPER_TYPE_MAP.put(Void.class, void.class);
     }
 
-    public boolean isPrimitiveType(Class<?> sourceClass) {
-        return WRAPPER_TYPE_MAP.containsKey(sourceClass);
+    public static boolean isPrimitiveType(Object source) {
+        return WRAPPER_TYPE_MAP.containsKey(source.getClass());
     }
 
 }
diff --git a/core-java-modules/core-java-lang-oop-types/src/test/java/com/baeldung/primitivetype/PrimitiveTypeUnitTest.java b/core-java-modules/core-java-lang-oop-types/src/test/java/com/baeldung/primitivetype/PrimitiveTypeUnitTest.java
index 5bbededbb3..b9152d3674 100644
--- a/core-java-modules/core-java-lang-oop-types/src/test/java/com/baeldung/primitivetype/PrimitiveTypeUnitTest.java
+++ b/core-java-modules/core-java-lang-oop-types/src/test/java/com/baeldung/primitivetype/PrimitiveTypeUnitTest.java
@@ -4,37 +4,31 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import org.apache.commons.lang3.ClassUtils;
-import org.junit.Before;
+import org.apache.commons.lang3.StringUtils;
 import org.junit.Test;
 
 import com.google.common.primitives.Primitives;
 
 public class PrimitiveTypeUnitTest {
 
-    private PrimitiveTypeUtil primitiveTypeUtil;
-
-    @Before
-    public void setup() {
-        primitiveTypeUtil = new PrimitiveTypeUtil();
-    }
-
     @Test
     public void givenAClass_whenCheckWithPrimitiveTypeUtil_thenShouldValidate() {
-        assertTrue(primitiveTypeUtil.isPrimitiveType(Boolean.class));
-        assertFalse(primitiveTypeUtil.isPrimitiveType(String.class));
+        assertTrue(PrimitiveTypeUtil.isPrimitiveType(false));
+        assertTrue(PrimitiveTypeUtil.isPrimitiveType(1L));
+        assertFalse(PrimitiveTypeUtil.isPrimitiveType(StringUtils.EMPTY));
     }
 
     @Test
     public void givenAClass_whenCheckWithCommonsLang_thenShouldValidate() {
-        assertTrue(ClassUtils.isPrimitiveOrWrapper(Boolean.class));
+        assertTrue(ClassUtils.isPrimitiveOrWrapper(Boolean.FALSE.getClass()));
         assertTrue(ClassUtils.isPrimitiveOrWrapper(boolean.class));
-        assertFalse(ClassUtils.isPrimitiveOrWrapper(String.class));
+        assertFalse(ClassUtils.isPrimitiveOrWrapper(StringUtils.EMPTY.getClass()));
     }
 
     @Test
     public void givenAClass_whenCheckWithGuava_thenShouldValidate() {
-        assertTrue(Primitives.isWrapperType(Boolean.class));
-        assertFalse(Primitives.isWrapperType(String.class));
-        assertFalse(Primitives.isWrapperType(boolean.class));
+        assertTrue(Primitives.isWrapperType(Boolean.FALSE.getClass()));
+        assertFalse(Primitives.isWrapperType(StringUtils.EMPTY.getClass()));
+        assertFalse(Primitives.isWrapperType(Boolean.TYPE.getClass()));
     }
 }