diff --git a/core-java-modules/core-java-serialization/pom.xml b/core-java-modules/core-java-serialization/pom.xml
index 74a78e8b48..8fcebca356 100644
--- a/core-java-modules/core-java-serialization/pom.xml
+++ b/core-java-modules/core-java-serialization/pom.xml
@@ -12,7 +12,6 @@
         <groupId>com.baeldung.core-java-modules</groupId>
         <artifactId>core-java-modules</artifactId>
         <version>0.0.1-SNAPSHOT</version>
-        <relativePath>../</relativePath>
     </parent>
 
     <dependencies>
@@ -186,8 +185,8 @@
         <!-- maven plugins -->
         <javamoney.moneta.version>1.1</javamoney.moneta.version>
         <maven-javadoc-plugin.version>3.0.0-M1</maven-javadoc-plugin.version>
-        <source.version>1.8</source.version>
-        <target.version>1.8</target.version>
+<!--        <source.version>1.8</source.version>-->
+<!--        <target.version>1.8</target.version>-->
         <spring.core.version>4.3.20.RELEASE</spring.core.version>
     </properties>
 
diff --git a/core-java-modules/core-java-serialization/src/test/java/com/baeldung/deserialization/DeserializationUnitTest.java b/core-java-modules/core-java-serialization/src/test/java/com/baeldung/deserialization/DeserializationUnitTest.java
index cc45cbc8e0..89a603a298 100644
--- a/core-java-modules/core-java-serialization/src/test/java/com/baeldung/deserialization/DeserializationUnitTest.java
+++ b/core-java-modules/core-java-serialization/src/test/java/com/baeldung/deserialization/DeserializationUnitTest.java
@@ -25,7 +25,7 @@ public class DeserializationUnitTest {
     @Test
     public void testDeserializeObj_compatible() throws IOException, ClassNotFoundException {
 
-        Assert.assertEquals(userDefinedSerialVersionUID, AppleProduct.getSerialVersionUID());
+        assertEquals(userDefinedSerialVersionUID, AppleProduct.getSerialVersionUID());
 
         AppleProduct macBook = new AppleProduct();
         macBook.headphonePort = "headphonePort2020";
@@ -61,7 +61,7 @@ public class DeserializationUnitTest {
     @Test(expected = InvalidClassException.class)
     public void testDeserializeObj_incompatible() throws ClassNotFoundException, IOException {
 
-        Assert.assertNotEquals(userDefinedSerialVersionUID, AppleProduct.getSerialVersionUID());
+        assertNotEquals(userDefinedSerialVersionUID, AppleProduct.getSerialVersionUID());
         // attempts to deserialize the "AppleProduct" object
         DeserializationUtility.deSerializeObjectFromString(serializedObj);
     }
diff --git a/core-java-modules/core-java-serialization/src/test/java/com/baeldung/externalizable/ExternalizableUnitTest.java b/core-java-modules/core-java-serialization/src/test/java/com/baeldung/externalizable/ExternalizableUnitTest.java
new file mode 100644
index 0000000000..651364fb13
--- /dev/null
+++ b/core-java-modules/core-java-serialization/src/test/java/com/baeldung/externalizable/ExternalizableUnitTest.java
@@ -0,0 +1,71 @@
+package com.baeldung.externalizable;
+
+import org.junit.Test;
+
+import java.io.*;
+
+import static org.junit.Assert.assertTrue;
+
+public class ExternalizableUnitTest {
+
+    private final static String OUTPUT_FILE = "externalizable.txt";
+
+    @Test
+    public void whenSerializing_thenUseExternalizable() throws IOException, ClassNotFoundException {
+
+        Country c = new Country();
+        c.setCapital("Yerevan");
+        c.setCode(374);
+        c.setName("Armenia");
+
+        FileOutputStream fileOutputStream = new FileOutputStream(OUTPUT_FILE);
+        ObjectOutputStream objectOutputStream = new ObjectOutputStream(fileOutputStream);
+        c.writeExternal(objectOutputStream);
+
+        objectOutputStream.flush();
+        objectOutputStream.close();
+        fileOutputStream.close();
+
+        FileInputStream fileInputStream = new FileInputStream(OUTPUT_FILE);
+        ObjectInputStream objectInputStream = new ObjectInputStream(fileInputStream);
+
+        Country c2 = new Country();
+        c2.readExternal(objectInputStream);
+
+        objectInputStream.close();
+        fileInputStream.close();
+
+        assertTrue(c2.getCode() == c.getCode());
+        assertTrue(c2.getName().equals(c.getName()));
+    }
+
+    @Test
+    public void whenInheritanceSerialization_then_UseExternalizable() throws IOException, ClassNotFoundException {
+
+        Region r = new Region();
+        r.setCapital("Yerevan");
+        r.setCode(374);
+        r.setName("Armenia");
+        r.setClimate("Mediterranean");
+        r.setPopulation(120.000);
+
+        FileOutputStream fileOutputStream = new FileOutputStream(OUTPUT_FILE);
+        ObjectOutputStream objectOutputStream = new ObjectOutputStream(fileOutputStream);
+        r.writeExternal(objectOutputStream);
+
+        objectOutputStream.flush();
+        objectOutputStream.close();
+        fileOutputStream.close();
+
+        FileInputStream fileInputStream = new FileInputStream(OUTPUT_FILE);
+        ObjectInputStream objectInputStream = new ObjectInputStream(fileInputStream);
+
+        Region r2 = new Region();
+        r2.readExternal(objectInputStream);
+
+        objectInputStream.close();
+        fileInputStream.close();
+
+        assertTrue(r2.getPopulation() == null);
+    }
+}
diff --git a/core-java-modules/core-java-uuid/pom.xml b/core-java-modules/core-java-uuid/pom.xml
index fba36ada8e..a38306f269 100644
--- a/core-java-modules/core-java-uuid/pom.xml
+++ b/core-java-modules/core-java-uuid/pom.xml
@@ -149,8 +149,6 @@
     <properties>
         <assertj-core.version>3.10.0</assertj-core.version>
         <maven-javadoc-plugin.version>3.0.0-M1</maven-javadoc-plugin.version>
-        <source.version>1.8</source.version>
-        <target.version>1.8</target.version>
     </properties>
 
 </project>
\ No newline at end of file