Almost done

src/main/java/com/zipcoder/payment/Check.java

     String accountNumber;
     int compare;
 
-    public Check(){
-        id = 12345;
-        payerName = "Tia Mowry";
-        routingNumber = "987654321";
-        accountNumber = "0123456789";
+    public Check(long id, String payerName, String accountNumber, String routingNumber ){
+        this.id = 12345;
+        this.payerName = "Tia Mowry";
+        this.routingNumber = "987654321";
+        this.accountNumber = "0123456789";
         compare = 0;
     }
 
+    public Check() {
+
+    }
+
+
+    public String getLastFour(String accountNumber){
+    return accountNumber.replace(accountNumber.substring(0, accountNumber.length()-4), "");
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/com/zipcoder/payment/PayPal.java

         compare = 0;
     }
 
+    public PayPal(long id, String payerName, String email) {
+        this.id = id;
+        this.payerName = payerName;
+        this.email = email;
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/com/zipcoder/payment/PaymentPresenter.java

 package com.zipcoder.payment;
+import java.util.Arrays;
 
 public class PaymentPresenter {
+    public String toString(Payment[] payments){
+        Arrays.sort(payments);
+        StringBuilder builder = new StringBuilder();
+        for(Payment o: payments){
+            o.getId();
+            o.getPayerName();
+            builder.append(o.getShortDescription()+ "\n");
+        }
+        return builder.toString();
+    }
 
+    public String toStringByPayerName(Payment[] payments){
+        Arrays.sort(payments, new PaymentSortByPayer());
+        StringBuilder builder = new StringBuilder();
+        for (Payment o: payments){
+            builder.append(o.getShortDescription()+ "\n");
+        }
+        return builder.toString();
+    }
+
+    public String toStringById(Payment[] payments){
+        Arrays.sort(payments, (Payment a, Payment b) -> Long.compare(a.getId(), b.getId()));
+        StringBuilder builder = new StringBuilder();
+        for (Payment o: payments){
+            builder.append(o.getShortDescription()+ "\n");
+        }
+        return builder.toString();
+    }
 }

src/main/java/com/zipcoder/payment/PaymentSortByPayer.java

+package com.zipcoder.payment;
+import java.util.Comparator;
+
+
+public class PaymentSortByPayer implements Comparator<Payment>{
+
+    @Override
+    public int compare(Payment o1, Payment o2){
+        return o1.getPayerName().compareTo(o2.getPayerName());
+    }
+}

src/test/java/com/zipcoder/payment/PaymentPresenterTest.java

 import static org.junit.Assert.*;
 
 
-public class PaymentPresenterTest1 {
+public class PaymentPresenterTest {
 
     @Test
     public void toString1() {
-        Payment[] payments = new payment.Payment[0];
+        Payment[] payments = new Payment[0];
         PaymentPresenter presenter = new PaymentPresenter();
         String expected = "";
 
 
     @Test
     public void toString2(){
-        Payment[] payments = new com.zipcoder.payment.Payment[2];
-        Payment payPal = new PayPayl(4L, "Tia Mowry", "tia@mowry.com");
-        Payment check = new Check(81L, "Tia Mowry", "11432543", "134344551")
+        Payment[] payments = new Payment[2];
+        Payment PayPal = new PayPal(4L, "Tia Mowry", "tia@mowry.com");
+        Payment check = new Check(81L, "Tia Mowry", "11432543", "134344551");
 
-        payment[0] = payPal;
-        payment[1] = check;
+        payments[0] = PayPal;
+        payments[1] = check;
 
         PaymentPresenter presenter = new PaymentPresenter();
         String expected = "Check Tia Mowry ***4551\nPaypal Tia Mowry tia@mowry.com\n";
 
     @Test
     public void toStringByPayerName() {
-        Payment[] payments = new com.zipcoder.payment.Payment[2];
-        Payment paypal = new PayPayl(4L, "Tamara Mowry", "tamara@mowry.com");
-        Payment check = new Check(81L, "Tia Mowry", "11432543", "134344551")
+        Payment[] payments = new Payment[2];
+        Payment paypal = new PayPal(4L, "Tamara Mowry", "tamara@mowry.com");
+        Payment check = new Check(81L, "Tia Mowry", "11432543", "134344551");
 
-        payment[0] = paypal;
-        payment[1] = check;
+        payments[0] = paypal;
+        payments[1] = check;
 
         PaymentPresenter presenter = new PaymentPresenter();
         String expected = "Paypal Tamara Mowry tamara@mowry.com\nCheck Tia Mowry ***4551\n";
 
     @Test
     public void toStringById(){
-        Payment[] payments = new com.zipcoder.payment.Payment[2];
-        Payment paypal = new PayPayl(120L, "Tamara Mowry", "tamara@mowry.com");
-        Payment check = new Check(81L, "Tia Mowry", "11432543", "134344551")
+        Payment[] payments = new Payment[2];
+        Payment paypal = new PayPal(120L, "Tamara Mowry", "tamara@mowry.com");
+        Payment check = new Check(81L, "Tia Mowry", "11432543", "134344551");
 
-        payment[0] = paypal;
-        payment[1] = check;
+        payments[0] = paypal;
+        payments[1] = check;
 
         PaymentPresenter presenter = new PaymentPresenter();
         String expected = "Paypal Tamara Mowry tamara@mowry.com\nCheck Tia Mowry ***4551\n";