visibility of variables of classes are private

java/src/main/java/Invoice.java

@@ -2,11 +2,19 @@ import java.util.List;
 
 public class Invoice {
 
-    public String customer;
+    private String customer;
-    public List<Performance> performances;
+    private List<Performance> performances;
 
     public Invoice(String customer, List<Performance> performances) {
         this.customer = customer;
         this.performances = performances;
     }
+
+    public String getCustomer() {
+        return customer;
+    }
+
+    public List<Performance> getPerformances() {
+        return performances;
+    }
 }

java/src/main/java/Performance.java

@@ -1,10 +1,18 @@
 public class Performance {
 
-    public String playID;
+    private String playID;
-    public int audience;
+    private int audience;
 
     public Performance(String playID, int audience) {
         this.playID = playID;
         this.audience = audience;
     }
+
+    public String getPlayID() {
+        return playID;
+    }
+
+    public int getAudience() {
+        return audience;
+    }
 }

java/src/main/java/Play.java

@@ -1,10 +1,18 @@
 public class Play {
 
-    public String name;
+    private String name;
-    public String type;
+    private String type;
 
     public Play(String name, String type) {
         this.name = name;
         this.type = type;
     }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getType() {
+        return type;
+    }
 }

java/src/main/java/StatementPrinter.java

@@ -7,39 +7,39 @@ public class StatementPrinter {
     public String print(Invoice invoice, Map<String, Play> plays) {
         var totalAmount = 0;
         var volumeCredits = 0;
-        var result = String.format("Statement for %s\n", invoice.customer);
+        var result = String.format("Statement for %s\n", invoice.getCustomer());
 
         NumberFormat frmt = NumberFormat.getCurrencyInstance(Locale.US);
 
-        for (var perf : invoice.performances) {
+        for (var perf : invoice.getPerformances()) {
-            var play = plays.get(perf.playID);
+            var play = plays.get(perf.getPlayID());
             var thisAmount = 0;
 
-            switch (play.type) {
+            switch (play.getType()) {
                 case "tragedy":
                     thisAmount = 40000;
-                    if (perf.audience > 30) {
+                    if (perf.getAudience() > 30) {
-                        thisAmount += 1000 * (perf.audience - 30);
+                        thisAmount += 1000 * (perf.getAudience() - 30);
                     }
                     break;
                 case "comedy":
                     thisAmount = 30000;
-                    if (perf.audience > 20) {
+                    if (perf.getAudience() > 20) {
-                        thisAmount += 10000 + 500 * (perf.audience - 20);
+                        thisAmount += 10000 + 500 * (perf.getAudience() - 20);
                     }
-                    thisAmount += 300 * perf.audience;
+                    thisAmount += 300 * perf.getAudience();
                     break;
                 default:
                     throw new Error("unknown type: ${play.type}");
             }
 
             // add volume credits
-            volumeCredits += Math.max(perf.audience - 30, 0);
+            volumeCredits += Math.max(perf.getAudience() - 30, 0);
             // add extra credit for every ten comedy attendees
-            if ("comedy".equals(play.type)) volumeCredits += Math.floor(perf.audience / 5);
+            if ("comedy".equals(play.getType())) volumeCredits += Math.floor(perf.getAudience() / 5);
 
             // print line for this order
-            result += String.format("  %s: %s (%s seats)\n", play.name, frmt.format(thisAmount / 100), perf.audience);
+            result += String.format("  %s: %s (%s seats)\n", play.getName(), frmt.format(thisAmount / 100), perf.getAudience());
             totalAmount += thisAmount;
         }
         result += String.format("Amount owed is %s\n", frmt.format(totalAmount / 100));