Reduced visibility of methods in PrimeGame to package private

src/main/java/io/fp/Primzahlen/PrimeGame.java

@@ -27,7 +27,7 @@ public class PrimeGame {
         this.currentLevel = currentLevel;
     }
 
-    public void nextCurrentLevel() {
+    void nextCurrentLevel() {
         currentLevel = currentLevel.getNextLevel();
     }
 
@@ -49,7 +49,7 @@ public class PrimeGame {
      * }
      */
 
-    public static boolean isPrime(int number) {
+    static boolean isPrime(int number) {
         for (int i = 2; i < number; i++) {
             if (number % i == 0) {
                 return false;
@@ -58,7 +58,7 @@ public class PrimeGame {
         return true;
     }
 
-    public void nextCurrentNumber() {
+    void nextCurrentNumber() {
         Random rand = new Random();
         switch (currentLevel) {
             case SIMPLE: