BAEL-2330 (#5694)

* Implementing Hexagonal Architecture in java

* Removing duplicates from a string

* Fix for the code review feedback
- removing the hexagonal architecture code
- removing the methods removeDuplicatesUsingCharArray
- adding some meaningful sentences to test

* Fix for the code review feedback
- fix for removeDuplicatesUsingCharArray
- adding unit testing
- adding brackets around for loops

* Fix for the code review feedback

java-strings/src/main/java/com/baeldung/stringduplicates/RemoveDuplicateFromString.java

@@ -0,0 +1,95 @@
+package com.baeldung.stringduplicates;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.LinkedHashSet;
+import java.util.Set;
+
+public class RemoveDuplicateFromString {
+
+
+    String removeDuplicatesUsingCharArray(String str) {
+
+        char[] chars = str.toCharArray();
+        StringBuilder sb = new StringBuilder();
+        int repeatedCtr;
+        for (int i = 0; i < chars.length; i++) {
+            repeatedCtr = 0;
+            for (int j = i + 1; j < chars.length; j++) {
+                if (chars[i] == chars[j]) {
+                    repeatedCtr++;
+                }
+            }
+            if (repeatedCtr == 0) {
+                sb.append(chars[i]);
+            }
+        }
+        return sb.toString();
+    }
+
+    String removeDuplicatesUsinglinkedHashSet(String str) {
+
+        StringBuilder sb = new StringBuilder();
+        Set<Character> linkedHashSet = new LinkedHashSet<>();
+
+        for (int i = 0; i < str.length(); i++) {
+            linkedHashSet.add(str.charAt(i));
+        }
+
+        for (Character c : linkedHashSet) {
+            sb.append(c);
+        }
+
+        return sb.toString();
+    }
+
+    String removeDuplicatesUsingSorting(String str) {
+
+        char[] chars = str.toCharArray();
+
+        Arrays.sort(chars);
+
+        StringBuilder sb = new StringBuilder();
+        sb.append(chars[0]);
+        for (int i = 1; i < chars.length; i++) {
+            if (chars[i] != chars[i - 1]) {
+                sb.append(chars[i]);
+            }
+        }
+
+        return sb.toString();
+    }
+
+    String removeDuplicatesUsingHashSet(String str) {
+
+        StringBuilder sb = new StringBuilder();
+        Set<Character> hashSet = new HashSet<>();
+
+        for (int i = 0; i < str.length(); i++) {
+            hashSet.add(str.charAt(i));
+        }
+
+        for (Character c : hashSet) {
+            sb.append(c);
+        }
+
+        return sb.toString();
+    }
+
+    String removeDuplicatesUsingIndexOf(String str) {
+
+        StringBuilder sb = new StringBuilder();
+        int idx;
+        for (int i = 0; i < str.length(); i++) {
+            char c = str.charAt(i);
+            idx = str.indexOf(c, i + 1);
+            if (idx == -1) {
+                sb.append(c);
+            }
+        }
+        return sb.toString();
+    }
+
+}
+
+