Add JsonSerializer example

lang/src/main/java/patternmatching/Statistics.java

@@ -1,6 +1,5 @@
 package patternmatching;
 
-import java.io.FileNotFoundException;
 import java.util.Arrays;
 import java.util.stream.Collectors;
 
@@ -14,7 +13,7 @@ public final class Statistics {
         this.data = data;
     }
 
-    double getMean() {
+    private double getMean() {
         if (mean == null) {
             mean = (double) Arrays.stream(data).sum() / data.length;
         }
@@ -22,7 +21,7 @@ public final class Statistics {
         return mean;
     }
 
-    double getVariance() {
+    private double getVariance() {
         if (variance == null) {
             final double mean = getMean();
             double temp = 0;
@@ -35,11 +34,11 @@ public final class Statistics {
         return variance;
     }
 
-    double getStddev() {
+    private double getStddev() {
         return Math.sqrt(getVariance());
     }
 
-    double getMedian() {
+    private double getMedian() {
         Arrays.sort(data);
         if (data.length % 2 == 0) return (data[(data.length / 2) - 1] + data[data.length / 2]) / 2.0;
         return data[data.length / 2];
@@ -59,8 +58,9 @@ public final class Statistics {
         );
     }
 
-    public String asCSv() {
-        final String csv = Arrays.stream(data).mapToObj(String::valueOf).collect(Collectors.joining(","));
-        return csv;
+    String asCSv() {
+        return Arrays.stream(data)
+                .mapToObj(String::valueOf)
+                .collect(Collectors.joining(","));
     }
 }