pom.xml

             <version>4.12</version>
             <scope>test</scope>
         </dependency>
+        <!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>3.8.1</version>
+        </dependency>
     </dependencies>
 
 

src/main/java/rocks/zipcode/quiz5/arrays/ArrayUtils.java

 package rocks.zipcode.quiz5.arrays;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
 /**
  * @author leon on 01/01/2019.
  */
 public class ArrayUtils {
     public static String getMiddleElement(String[] values) {
-        return null;
+        int middleIndex = values.length/2;
+        return values[middleIndex];
     }
 
     public static String[] removeMiddleElement(String[] values) {
-        return null;
+        int middleIndex = values.length/2;
+        String[] results = Arrays.copyOf(values,values.length-1);
+        for (int i = 0; i < results.length; i++) {
+            if(i >= middleIndex){
+                results[i]=values[i+1];
+            }
+        }
+
+        return results;
     }
 
     public static String getLastElement(String[] values) {
-        return null;
+        return values[values.length-1];
     }
 
     public static String[] removeLastElement(String[] values) {
-        return null;
+        String[] result = Arrays.copyOfRange(values,0,values.length-1);
+        return result;
     }
 }

src/main/java/rocks/zipcode/quiz5/collections/Bank.java

 
 import rocks.zipcode.quiz5.objectorientation.account.BankAccount;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * @author leon on 27/12/2018.
  */
 public class Bank {
+    List<BankAccount> bankAccounts = new ArrayList<>();
+
     public BankAccount removeBankAccountByIndex(Integer indexNumber) {
+        for (int i = 0; i < bankAccounts.size(); i++) {
+            if(i == indexNumber){
+                bankAccounts.remove(i);
+            }
+        }
         return null;
     }
 
     public void addBankAccount(BankAccount bankAccount) {
+        bankAccounts.add(bankAccount);
     }
 
     public Boolean containsBankAccount(BankAccount bankAccount) {
-        throw new UnsupportedOperationException("Method not yet implemented");
+        return bankAccounts.contains(bankAccount);
     }
 }

src/main/java/rocks/zipcode/quiz5/collections/Food.java

 
 import rocks.zipcode.quiz5.objectorientation.Spice;
 
+import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
  * @author leon on 27/12/2018.
  */
 public class Food {
+    List<Spice> spiceList = new ArrayList<>();
+
     public List<Spice> getAllSpices() {
-        return null;
+        return spiceList;
     }
 
     public <SpiceType extends Class<? extends Spice>> Map<SpiceType, Integer> getSpiceCount() {
+        Map<SpiceType,Integer> spicesCount = new HashMap<>();
+
+//        for (int i = 0; i < spiceList.size(); i++) {
+//            if(!spicesCount.containsKey(spiceList.get(i))) {
+//                spicesCount.put(spiceList.get(i), 1);
+//            }else
+//                spicesCount.put(spiceList.get(i), spicesCount.get(i)+1);
+//        }
         return null;
     }
 
     public void applySpice(Spice spice) {
+        spiceList.add(spice);
     }
 }

src/main/java/rocks/zipcode/quiz5/collections/WordCounter.java

 package rocks.zipcode.quiz5.collections;
-
+import java.util.HashMap;
 import java.util.Map;
 
+
 public class WordCounter {
+    Map<String, Integer> words = new HashMap<>();
+
     public WordCounter(String... strings) {
+        for(String str: strings){
+            if(!words.containsKey(str)){
+                words.put(str,1);
+            }else{
+                words.put(str,words.get(str)+1);
+            }
+        }
     }
 
     public Map<String, Integer> getWordCountMap() {
-        return null;
+
+        return words;
     }
 }

src/main/java/rocks/zipcode/quiz5/fundamentals/Calculator.java

  */
 public class Calculator {
     public static Double squareRoot(Double value) {
-        return null;
+
+        return Math.sqrt(value);
     }
 
     public static Double square(Double value) {
-        return null;
+
+        return value*value;
     }
 
     public static Double[] squareRoots(Double... value) {
-        return null;
+        Double[] results = new Double[value.length];
+        for (int i = 0; i < value.length; i++) {
+            results[i] = Math.sqrt(value[i]);
+        }
+        return results;
     }
 
     public static Double[] squares(Double... values) {
-        return null;
+        Double[] results = new Double[values.length];
+        for (int i = 0; i < values.length; i++) {
+            results[i] = values[i]*values[i];
+        }
+        return results;
     }
 
     public static Double add(Double value1, Double value2) {
-        return null;
+        return value1+value2;
     }
 
     public static Double subtract(Double value1, Double value2) {
-        return null;
+        return value1-value2;
     }
 
-
     public static Double divide(Double divisor, Double dividend) {
-        return null;
+        return divisor/dividend;
     }
 }

src/main/java/rocks/zipcode/quiz5/fundamentals/StringUtils.java

  */
 public class StringUtils {
     public static Character getMiddleCharacter(String string) {
-        return null;
+
+        return string.charAt(string.length()/2);
     }
 
     public static String capitalizeMiddleCharacter(String str) {
-        return null;
+        return str.substring(0, str.length()/2) + getMiddleCharacter(str)
+                .toString().toUpperCase() + str.substring(str.length()/2 + 1);
     }
 
     public static String lowerCaseMiddleCharacter(String str) {
-        return null;
+        return str.substring(0, str.length()/2) + getMiddleCharacter(str)
+                .toString().toLowerCase() + str.substring(str.length()/2 + 1);
     }
 
     public static Boolean isIsogram(String str) {
-        return null;
+        for (int i = 0; i < str.length(); i++) {
+            for (int j = 1; j < str.length(); j++) {
+                if(str.charAt(i)!=str.charAt(j)){
+                    return true;
+                }
+            }
+        }
+        return false;
     }
 
     public static Boolean hasDuplicateConsecutiveCharacters(String str) {
-        return null;
+        boolean hasDupl = false;
+        char[] chars = str.toCharArray();
+        for (int i = 1; i < chars.length-1; i++) {
+            if(chars[i]==chars[i+1]){
+                hasDupl =  true;
+                break;
+            }
+        }
+        return hasDupl;
     }
 
     public static String removeConsecutiveDuplicateCharacters(String str) {
-        return null;
+        String[] words = str.split("");
+        StringBuilder builder = new StringBuilder();
+        for (int i = 0; i < words.length-1; i++) {
+            if(words[i].equals(words[i+1])){
+                i++;
+            }else
+                builder.append(words[i]);
+        }
+        builder.append(words[words.length-1]);
+        return builder.toString();
     }
 
     public static String invertCasing(String str) {
-        return null;
+        return org.apache.commons.lang3.StringUtils.swapCase(str);
     }
 }

src/main/java/rocks/zipcode/quiz5/objectorientation/Curry.java

 package rocks.zipcode.quiz5.objectorientation;
 
-public class Curry {
+public class Curry implements Spice {
 }

src/main/java/rocks/zipcode/quiz5/objectorientation/Ginger.java

 /**
  * @author leon on 27/12/2018.
  */
-public class Ginger {
+public class Ginger implements Spice{
 }

src/main/java/rocks/zipcode/quiz5/objectorientation/Pepper.java

 /**
  * @author leon on 27/12/2018.
  */
-public class Pepper {
+public class Pepper implements Spice{
 }

src/main/java/rocks/zipcode/quiz5/objectorientation/account/Account.java

 /**
  * @author leon on 30/12/2018.
  */
-public class Account extends BankAccount {
+public class Account {
+    private Double balance;
+    private Long id;
+
+    public Account() {
+        this.balance = 0.0;
+    }
+
+    public Account(Double balance, Long id) {
+        this.balance = balance;
+        this.id = id;
+    }
+
     public Long getId() {
-        return null;
+        return id;
     }
 
     public void setId(Long id) {
+        this.id = id;
     }
+
 }

src/main/java/rocks/zipcode/quiz5/objectorientation/account/BankAccount.java

 /**
  * @author leon on 27/12/2018.
  */
-public class BankAccount {
+public class BankAccount extends Account implements Transactable{
+    private Double balance;
+    private Long id;
+
+    public BankAccount(Double balance, Long id) {
+        this.balance = balance;
+        this.id = id;
+    }
+
+    public BankAccount() {
+        this.balance = 0.0;
+    }
+
     public void setBalance(Double val) {
+        this.balance = val;
+    }
+
+    @Override
+    public void deposit(Double amountToIncreaseBy) {
+        if(amountToIncreaseBy<=0){
+            throw new IllegalArgumentException();
+        }
+        balance = balance+amountToIncreaseBy;
+    }
+
+    @Override
+    public void withdrawal(Double amountToDecreaseBy) {
+        if(amountToDecreaseBy>balance){
+            throw new IllegalArgumentException();
+        }else if(amountToDecreaseBy<0){
+            throw new IllegalArgumentException();
+        }
+        balance = balance-amountToDecreaseBy;
+    }
+
+    @Override
+    public Double getBalance() {
+        return balance;
     }
 }

src/main/java/rocks/zipcode/quiz5/objectorientation/account/Employee.java

 /**
  * @author leon on 30/12/2018.
  */
-public class Employee {
+public class Employee implements Transactable, Worker{
+    private Double hourlyWage = 35.0;
+    private Double hoursWorked = 0.0;
+    private BankAccount bankAccount;
+
     public Employee() {
+        this.bankAccount = new BankAccount();
+
     }
 
     public Employee(BankAccount bankAccount) {
+        this.bankAccount = bankAccount;
     }
 
     public BankAccount getBankAccount() {
-        return null;
+        return bankAccount;
     }
 
     public void setBankAccount(BankAccount bankAccount) {
+        this.bankAccount = bankAccount;
+    }
+
+    @Override
+    public void deposit(Double amountToIncreaseBy) {
+        bankAccount.deposit(amountToIncreaseBy);
+    }
+
+    @Override
+    public void withdrawal(Double amountToDecreaseBy) {
+        bankAccount.withdrawal(amountToDecreaseBy);
+    }
+
+    @Override
+    public Double getBalance() {
+        return bankAccount.getBalance();
+    }
+
+    @Override
+    public void increaseHoursWorked(Double numberOfHours) {
+        hoursWorked = hoursWorked + numberOfHours;
+    }
+
+    @Override
+    public Double getHoursWorked() {
+        return hoursWorked;
+    }
+
+    @Override
+    public Double getHourlyWage() {
+        return hourlyWage;
+    }
 
+    @Override
+    public Double getMoneyEarned() {
+        return hourlyWage*hoursWorked;
     }
 }