All steps completed, brain melted

interfaces-1.iml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module org.jetbrains.idea.maven.project.MavenProjectsManager.isMavenModule="true" type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_11">
+    <output url="file://$MODULE_DIR$/target/classes" />
+    <output-test url="file://$MODULE_DIR$/target/test-classes" />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src/main/java" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/src/test/java" isTestSource="true" />
+      <excludeFolder url="file://$MODULE_DIR$/target" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" scope="TEST" name="Maven: junit:junit:4.12" level="project" />
+    <orderEntry type="library" scope="TEST" name="Maven: org.hamcrest:hamcrest-core:1.3" level="project" />
+  </component>
+</module>

pom.xml

@@ -5,6 +5,18 @@
   <groupId>io.zipcoder</groupId>
   <artifactId>interfaces-1</artifactId>
   <version>0.0.1-SNAPSHOT</version>
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <configuration>
+          <source>11</source>
+          <target>11</target>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
   <packaging>jar</packaging>
 
   <name>interfaces-1</name>

src/main/java/io/zipcoder/interfaces/Educator.java

@@ -0,0 +1,28 @@
+package io.zipcoder.interfaces;
+
+public enum Educator implements Teacher{
+    DOLIO( new Instructor(1l, "Dolio")),
+    LEON(new Instructor(2l, "Leon")),
+    OTHERDOLIO(new Instructor(3l, "OtherDolio"));
+
+
+    final Instructor instructor;
+    double timeWorked;
+
+    Educator(Instructor instructor) {
+        this.instructor = instructor;
+        Instructors.getInstance().add(instructor);
+    }
+
+    @Override
+    public void teach(Learner learner, double numberOfHours) {
+        this.instructor.teach(learner, numberOfHours);
+        this.timeWorked += numberOfHours;
+    }
+
+    @Override
+    public void lecture(Learner[] learners, double numberOfHours) {
+        this.instructor.lecture(learners, numberOfHours);
+        this.timeWorked += numberOfHours;
+    }
+}

src/main/java/io/zipcoder/interfaces/Instructor.java

@@ -0,0 +1,21 @@
+package io.zipcoder.interfaces;
+
+public class Instructor extends Person implements Teacher{
+
+    public Instructor(Long id, String name) {
+        super(id, name);
+    }
+
+    @Override
+    public void teach(Learner learner, double numberOfHours) {
+        learner.learn(numberOfHours);
+    }
+
+    @Override
+    public void lecture(Learner[] learners, double numberOfHours) {
+        double numberOfHoursPerLearner = numberOfHours/ learners.length;
+        for(Learner element : learners){
+            element.learn(numberOfHoursPerLearner);
+        }
+    }
+}

src/main/java/io/zipcoder/interfaces/Instructors.java

@@ -0,0 +1,21 @@
+package io.zipcoder.interfaces;
+
+public final class Instructors extends People<Instructor>{
+    private static final Instructors INSTANCE = new Instructors();
+
+    private Instructors(){
+        this.add(new Instructor(1l,"Dolio"));
+        this.add(new Instructor(2l,"Leon"));
+        this.add(new Instructor(3l,"Other Dolio"));
+    }
+
+
+    public static Instructors getInstance(){
+        return INSTANCE;
+    }
+
+    @Override
+    public Instructor[] toArray() {
+        return new Instructor[0];
+    }
+}

src/main/java/io/zipcoder/interfaces/Learner.java

@@ -0,0 +1,6 @@
+package io.zipcoder.interfaces;
+
+public interface Learner {
+    void learn(double numberOfHours);
+    Double getTotalStudyTime();
+}