This PR is related to BAEL-5998 (#16384)

* This commit is related to BAEL-5998

This commit aims to add a class named "Employee".

* This commit is related to BAEL-5998

This commit aims to add a test class titled "PrintingNullValuesUnitTest".

* Update PrintingNullValuesUnitTest.java

core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/printnullvalues/Employee.java

@@ -0,0 +1,44 @@
+package com.baeldung.printnullvalues;
+
+import java.util.Objects;
+import java.util.Optional;
+
+public class Employee {
+    private String name;
+    private int age;
+    private String department;
+
+    public Employee(String name, int age, String department) {
+        this.name = name;
+        this.age = age;
+        this.department = department;
+    }
+
+    public String toStringUsingNullCheck() {
+        return "Name: " + (name != null ? name : "Unknown") +
+                ", Age: " + age +
+                ", Department: " + (department != null ? department : "Unknown");
+    }
+
+    public String toStringUsingOptional() {
+        return "Name: " + Optional.ofNullable(name).orElse("Unknown") +
+                ", Age: " + age +
+                ", Department: " + Optional.ofNullable(department).orElse("Unknown");
+    }
+
+    private String getDefaultIfNull(String value, String defaultValue) {
+        return value != null ? value : defaultValue;
+    }
+
+    public String toStringUsingCustomHelper() {
+        return "Name: " + getDefaultIfNull(name, "Unknown") +
+                ", Age: " + age +
+                ", Department: " + getDefaultIfNull(department, "Unknown");
+    }
+
+    public String toStringUsingObjects() {
+        return "Name: " + Objects.toString(name, "Unknown") +
+                ", Age: " + age +
+                ", Department: " + Objects.toString(department, "Unknown");
+    }
+}

core-java-modules/core-java-lang-oop-others/src/test/java/com/baeldung/printnullvalues/PrintingNullValuesUnitTest.java

@@ -0,0 +1,30 @@
+package com.baeldung.printnullvalues;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class PrintingNullValuesUnitTest {
+    Employee employee = new Employee(null, 30, null);
+    String expected = "Name: Unknown, Age: 30, Department: Unknown";
+
+    @Test
+    public void givenNullValues_whenToStringUsingNullCheck_thenCorrectStringReturned() {
+        assertEquals(expected, employee.toStringUsingNullCheck());
+    }
+
+    @Test
+    public void givenNullValues_whenToStringUsingOptional_thenCorrectStringReturned() {
+        assertEquals(expected, employee.toStringUsingOptional());
+    }
+
+    @Test
+    public void givenNullValues_whenToStringUsingCustomHelper_thenCorrectStringReturned() {
+        assertEquals(expected, employee.toStringUsingCustomHelper());
+    }
+
+    @Test
+    public void givenNullValues_whenToStringUsingObjects_thenCorrectStringReturned() {
+        assertEquals(expected, employee.toStringUsingObjects());
+    }
+}