Moved the HelpfulNullPointerException code to the npe package.

Merge remote-tracking branch 'upstream/master'

core-java-modules/core-java-14/README.md

@@ -7,3 +7,4 @@ This module contains articles about Java 14.
 - [Guide to the @Serial Annotation in Java 14](https://www.baeldung.com/java-14-serial-annotation)
 - [Java Text Blocks](https://www.baeldung.com/java-text-blocks)
 - [Pattern Matching for instanceof in Java 14](https://www.baeldung.com/java-pattern-matching-instanceof)
+- [Helpful NullPointerExceptions in Java 14](https://www.baeldung.com/java-14-nullpointerexception)

core-java-modules/core-java-14/src/main/java/com/baeldung/java14/npe/HelpfulNullPointerException.java

@@ -0,0 +1,56 @@
+package com.baeldung.java14.npe;
+
+public class HelpfulNullPointerException {
+
+    public static void main(String[] args) {
+        Employee employee = null;
+        employee.getName();
+    }
+
+    public String getEmployeeEmailAddress(Employee employee) {
+        String emailAddress = employee.getPersonalDetails().getEmailAddress().toLowerCase();
+        return emailAddress;
+    }
+
+    static class Employee {
+        String name;
+        PersonalDetails personalDetails;
+
+        public String getName() {
+            return name;
+        }
+
+        public void setName(String name) {
+            this.name = name;
+        }
+
+        public PersonalDetails getPersonalDetails() {
+            return personalDetails;
+        }
+
+        public void setPersonalDetails(PersonalDetails personalDetails) {
+            this.personalDetails = personalDetails;
+        }
+    }
+
+    static class PersonalDetails {
+        String emailAddress;
+        String phone;
+
+        public String getEmailAddress() {
+            return emailAddress;
+        }
+
+        public void setEmailAddress(String emailAddress) {
+            this.emailAddress = emailAddress;
+        }
+
+        public String getPhone() {
+            return phone;
+        }
+
+        public void setPhone(String phone) {
+            this.phone = phone;
+        }
+    }
+}

core-java-modules/core-java-14/src/test/java/com/baeldung/java14/npe/HelpfulNullPointerExceptionUnitTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.java14.npe;
+
+import org.junit.Test;
+
+import static com.baeldung.java14.helpfulnullpointerexceptions.HelpfulNullPointerException.Employee;
+import static com.baeldung.java14.helpfulnullpointerexceptions.HelpfulNullPointerException.PersonalDetails;
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class HelpfulNullPointerExceptionUnitTest {
+
+    @Test (expected = NullPointerException.class)
+    public void givenAnEmptyPersonalDetails_whenEmailAddressIsAccessed_thenThrowNPE() {
+        var helpfulNPE = new HelpfulNullPointerException();
+
+        var employee = new Employee();
+        employee.setName("Eduard");
+        employee.setPersonalDetails(new PersonalDetails());
+        helpfulNPE.getEmployeeEmailAddress(employee);
+    }
+
+    @Test
+    public void givenCompletePersonalDetails_whenEmailAddressIsAccessed_thenSuccess() {
+        var helpfulNPE = new HelpfulNullPointerException();
+        var emailAddress = "[email protected]";
+
+        var employee = new Employee();
+        employee.setName("Eduard");
+
+        var personalDetails = new PersonalDetails();
+        personalDetails.setEmailAddress(emailAddress.toUpperCase());
+        personalDetails.setPhone("1234");
+        employee.setPersonalDetails(personalDetails);
+
+        assertThat(helpfulNPE.getEmployeeEmailAddress(employee)).isEqualTo(emailAddress);
+    }
+
+}

core-java-modules/core-java-8-2/README.md

@@ -4,7 +4,6 @@ This module contains articles about Java 8 core features
 
 ### Relevant Articles: 
 
-- [How to Delay Code Execution in Java](https://www.baeldung.com/java-delay-code-execution)
 - [Run a Java Application from the Command Line](https://www.baeldung.com/java-run-jar-with-arguments)
 - [Java 8 Stream skip() vs limit()](https://www.baeldung.com/java-stream-skip-vs-limit)
 - [Guide to Java BiFunction Interface](https://www.baeldung.com/java-bifunction-interface)

core-java-modules/core-java-8-datetime-2/README.md

@@ -0,0 +1,5 @@
+### Relevant Articles:
+
+- [Generating Random Dates in Java](https://www.baeldung.com/java-random-dates)
+- [Creating a LocalDate with Values in Java](https://www.baeldung.com/java-creating-localdate-with-values)
+- [[<-- Prev]](/core-java-modules/core-java-datetime-java8-1)

core-java-modules/core-java-8-datetime-2/pom.xml

@@ -4,9 +4,9 @@
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
-    <artifactId>core-java-datetime-java8</artifactId>
+    <artifactId>core-java-8-datetime</artifactId>
     <version>${project.parent.version}</version>
-    <name>core-java-datetime-java8</name>
+    <name>core-java-8-datetime</name>
     <packaging>jar</packaging>
 
     <parent>
@@ -64,8 +64,8 @@
     </build>
 
     <properties>
-        <maven.compiler.source>1.9</maven.compiler.source>
-        <maven.compiler.target>1.9</maven.compiler.target>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
         <joda-time.version>2.10</joda-time.version>
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>

core-java-modules/core-java-8-datetime-2/src/test/java/com/baeldung/localdate/LocalDateExampleUnitTest.java

@@ -11,31 +11,31 @@ public class LocalDateExampleUnitTest {
 
     @Test
     public void givenValues_whenUsingOfMethod_thenLocalDate() {
-        assertEquals("2020-01-08", date.getCustomDateOne(2020, 1, 8));
+        assertEquals("2020-01-08", date.getCustomDateOne(2020, 1, 8).toString());
     }
 
     @Test
     public void givenValuesWithMonthEnum_whenUsingOfMethod_thenLocalDate() {
-        assertEquals("2020-01-08", date.getCustomDateTwo(2020, Month.JANUARY, 8));
+        assertEquals("2020-01-08", date.getCustomDateTwo(2020, Month.JANUARY, 8).toString());
     }
 
     @Test
     public void givenValues_whenUsingEpochDay_thenLocalDate() {
-        assertEquals("2020-01-08", date.getDateFromEpochDay(18269));
+        assertEquals("2020-01-08", date.getDateFromEpochDay(18269).toString());
     }
 
     @Test
     public void givenValues_whenUsingYearDay_thenLocalDate() {
-        assertEquals("2020-01-08", date.getDateFromYearAndDayOfYear(2020, 8));
+        assertEquals("2020-01-08", date.getDateFromYearAndDayOfYear(2020, 8).toString());
     }
 
     @Test
     public void givenValues_whenUsingParse_thenLocalDate() {
-        assertEquals("2020-01-08", date.getDateFromString("2020-01-08"));
+        assertEquals("2020-01-08", date.getDateFromString("2020-01-08").toString());
     }
 
     @Test
     public void givenValuesWithFormatter_whenUsingParse_thenLocalDate() {
-        assertEquals("2020-01-08", date.getDateFromStringAndFormatter("8-Jan-2020", "d-MMM-yyyy"));
+        assertEquals("2020-01-08", date.getDateFromStringAndFormatter("8-Jan-2020", "d-MMM-yyyy").toString());
     }
 }

core-java-modules/core-java-8-datetime/README.md

@@ -13,4 +13,4 @@ This module contains articles about the Date and Time API introduced with Java 8
 - [How to Get the Start and the End of a Day using Java](http://www.baeldung.com/java-day-start-end)
 - [Set the Time Zone of a Date in Java](https://www.baeldung.com/java-set-date-time-zone)
 - [Comparing Dates in Java](https://www.baeldung.com/java-comparing-dates)
-- [Generating Random Dates in Java](https://www.baeldung.com/java-random-dates)
+- [[Next -->]](/core-java-modules/core-java-datetime-java8-2)

core-java-modules/core-java-8-datetime/pom.xml

@@ -4,9 +4,9 @@
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
-    <artifactId>core-java-datetime-java8</artifactId>
+    <artifactId>core-java-8-datetime</artifactId>
     <version>${project.parent.version}</version>
-    <name>core-java-datetime-java8</name>
+    <name>core-java-8-datetime</name>
     <packaging>jar</packaging>
 
     <parent>
@@ -64,8 +64,8 @@
     </build>
 
     <properties>
-        <maven.compiler.source>1.9</maven.compiler.source>
-        <maven.compiler.target>1.9</maven.compiler.target>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
         <joda-time.version>2.10</joda-time.version>
         <!-- testing -->
         <assertj.version>3.6.1</assertj.version>