Chars in String

src/main/java/pl/pk/algorithms/arrays/arrayInArray/ArrayInArrayCompareMain.java

@@ -8,7 +8,7 @@ public class ArrayInArrayCompareMain {
     public static void main(String[] args) {
 
         int[] a1 = {1, 4, 6, 3, 7, 9, 1, 4};
-        int[] a2 = {1, 4};
+        int[] a2 = {1, 4, 6};
 
         IntsService intsService = new IntsService();
 

src/main/java/pl/pk/algorithms/numbers/charInString/HowManyTimeCharInString.java

@@ -0,0 +1,30 @@
+package pl.pk.algorithms.numbers.charInString;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class HowManyTimeCharInString {
+
+    public static void main(String[] args) {
+
+        String text = "abcdaabcd";
+        HashMap<String, Integer> resultMap = new HashMap<>();
+
+        for (int i = 0; i < text.length(); i++) {
+            char l = text.charAt(i);
+            String l2 = Character.toString(l);
+
+            if (resultMap.containsKey(l2)) {
+                int x = resultMap.get(l2);
+                x = x + 1;
+                resultMap.put(l2, x);
+            } else {
+                resultMap.put(l2, 1);
+            }
+        }
+
+        for (Map.Entry<String, Integer> entry: resultMap.entrySet()) {
+            System.out.println("Znak [" + entry.getKey() + "] is [" + entry.getValue() + "] times." );
+        }
+    }
+}

src/main/java/pl/pk/algorithms/patterns/PatternsMain.java

@@ -0,0 +1,13 @@
+package pl.pk.algorithms.patterns;
+
+public class PatternsMain {
+
+    public static void main(String[] args) {
+
+        SingletonImplementation singleton = SingletonImplementation.getINSTANCE();
+        SingletonImplementation singletonImplementation2 = SingletonImplementation.getINSTANCE();
+
+        singleton.showDesc();
+        System.out.println("It`s the same object? " + singleton.equals(singletonImplementation2));
+    }
+}

src/main/java/pl/pk/algorithms/patterns/SingletonImplementation.java

@@ -0,0 +1,30 @@
+package pl.pk.algorithms.patterns;
+
+import java.util.Random;
+
+public class SingletonImplementation {
+
+    private final String desc;
+    private static SingletonImplementation INSTANCE = null;
+
+    private SingletonImplementation() {
+        Random r = new Random();
+        this.desc = r.nextInt(1256) + "";
+    }
+
+    public static SingletonImplementation getINSTANCE() {
+        if (INSTANCE == null) {
+            synchronized (SingletonImplementation.class) {
+                if (INSTANCE == null) {
+                    INSTANCE = new SingletonImplementation();
+                }
+            }
+        }
+        return INSTANCE;
+    }
+
+    public void showDesc() {
+        System.out.println(desc);
+    }
+
+}