serialization code (#1844)

* adds serialization code

* fixes serialization unit test

* adds code for custom serialization

* changed test case names

* fixes test names

core-java/src/main/java/com/baeldung/serialization/Address.java

@@ -0,0 +1,15 @@
+package com.baeuldung.serialization;
+
+public class Address {
+
+	private int houseNumber;
+
+	public int getHouseNumber() {
+		return houseNumber;
+	}
+
+	public void setHouseNumber(int houseNumber) {
+		this.houseNumber = houseNumber;
+	}
+
+}

core-java/src/main/java/com/baeldung/serialization/Employee.java

@@ -0,0 +1,44 @@
+package com.baeuldung.serialization;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
+
+public class Employee implements Serializable {
+
+	private static final long serialVersionUID = 1L;
+
+	private transient Address address; // not an serializable object
+	private Person person;
+
+	public Address getAddress() {
+		return address;
+	}
+
+	public void setAddress(Address address) {
+		this.address = address;
+	}
+
+	public Person getPerson() {
+		return person;
+	}
+
+	public void setPerson(Person person) {
+		this.person = person;
+	}
+
+	private void writeObject(ObjectOutputStream oos) throws IOException {
+		oos.defaultWriteObject();
+		oos.writeObject(address.getHouseNumber());
+	}
+
+	private void readObject(ObjectInputStream ois) throws ClassNotFoundException, IOException {
+		ois.defaultReadObject();
+		Integer houseNumber = (Integer) ois.readObject();
+		Address a = new Address();
+		a.setHouseNumber(houseNumber);
+		this.setAddress(a);
+	}
+
+}