Removed code smells and followed naming convention

- Local variable names in java must be with the  default regular expression ^[a-z][a-zA-Z0-9]*$
https://rules.sonarsource.com/java/tag/convention/RSPEC-117
- The diamond operator ("<>") should be used when the type of the maps are already defined
https://rules.sonarsource.com/java/RSPEC-2293
- Package names being camel cased is a code smell

src/main/java/com/caching/LFUCache.java

@@ -75,8 +75,8 @@ class LFUCache<T> {
     public LFUCache(int capacity) {
         this.capacity = capacity;
         size = 0;
-        freq = new TreeMap<Integer, DLL>();
+        freq = new TreeMap<>();
-        map = new HashMap<Integer, Node>();
+        map = new HashMap<>();
         System.out.println("LFUCache initialised with capacity: " + capacity);
     }
 
@@ -145,8 +145,8 @@ class LFUCache<T> {
                 dll.deleteNode(dll.tail.pre);
                 if (dll.len == 0 && lowest != 1)
                     freq.remove(lowest);
-                DLL freq_one = freq.computeIfAbsent(1, k -> new DLL());
+                DLL freqOne = freq.computeIfAbsent(1, k -> new DLL());
-                freq_one.addToHead(node);
+                freqOne.addToHead(node);
             }
         }
 

src/main/java/com/ciphers/CaesarBruteForce.java

@@ -5,25 +5,25 @@ public class CaesarBruteForce {
     /**
      * Recursively Brute forces a parsed encrypted text, trying out all shifting keys from 1-26, printing out all decryption attempts
      * @param message (String) The encrypted text.
-     * @param Key (int) The key used to decrypt the encrypted text and is increment upon a recursive call.
+     * @param key (int) The key used to decrypt the encrypted text and is increment upon a recursive call.
      * @return (String) Concatenated string of all decryption attempts (For unit testing purposes).
      */
-    public String decrypt(String message, int Key) {
+    public String decrypt(String message, int key) {
         final String LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
-        if (Key > 26){ System.out.println(); return null; }
+        if (key > 26){ System.out.println(); return null; }
 
         StringBuilder plainText = new StringBuilder();
         for (char character : message.toUpperCase().toCharArray()) {
             int index = LETTERS.indexOf(character);
 
             if (index != -1) {
-                index -= Key;
+                index -= key;
                 //Wrap around index value range[1-26]
                 if (index < 0) { index += LETTERS.length(); }
                 plainText.append(LETTERS.toCharArray()[index]);
             } else { plainText.append(character); }
         }
-        System.out.println(String.format("Current Decryption Key %d : %s", Key, plainText));
+        System.out.println(String.format("Current Decryption Key %d : %s", key, plainText));
-        return plainText.append(decrypt(message, Key+1)).toString();
+        return plainText.append(decrypt(message, key+1)).toString();
     }
 }

src/main/java/com/conversions/HexadecimalToBinary.java

@@ -12,7 +12,7 @@ public class HexadecimalToBinary {
 	public String hexToBin (String hexStr) {
 		
 		String binaryString = "", hexaNumbers = "0123456789ABCDEF", 
-				DecimalStr ="", binaryStringBefore ="" , binaryStringAfter = "";
+				decimalStr ="", binaryStringBefore ="" , binaryStringAfter = "";
 		int indexOfHex, decimalNumber = 0, k = 1, n =1, z=1, decimalNumberBefore = 0
 				, decimalNumberAfter = 0;
 		char letter;
@@ -48,12 +48,12 @@ public class HexadecimalToBinary {
 
 			String decimalNumberAfterStr = String.valueOf(decimalNumberAfter);
 			
-			DecimalStr = decimalNumberBeforeStr + '.' + decimalNumberAfterStr;
+			decimalStr = decimalNumberBeforeStr + '.' + decimalNumberAfterStr;
 			}
 
 		
 		
-		int pointPositionDec = DecimalStr.indexOf(".");
+		int pointPositionDec = decimalStr.indexOf(".");
 		/**
 		 * Check whether the result contains a floating point or not
 		 */

src/main/java/com/datastructures/BinaryTree.java

@@ -1,4 +1,4 @@
-package com.dataStructures;
+package com.datastructures;
 
 /**
  * Binary tree for general value type, without redundancy

src/main/java/com/datastructures/DisjointSet.java

@@ -1,4 +1,4 @@
-package com.dataStructures;
+package com.datastructures;
 
 import java.io.Serializable;
 import java.util.*;

src/main/java/com/datastructures/GeneralQueue.java

@@ -1,4 +1,4 @@
-package com.dataStructures;
+package com.datastructures;
 
 import com.types.Queue;
 

src/main/java/com/datastructures/IntQueue.java

@@ -1,4 +1,4 @@
-package com.dataStructures;
+package com.datastructures;
 
 /**
  * This file contains an implementation of an integer only queue which is extremely quick and

src/main/java/com/datastructures/SinglyLinkedList.java

@@ -1,4 +1,4 @@
-package com.dataStructures;
+package com.datastructures;
 
 
 

src/main/java/com/datastructures/Stack.java

@@ -1,4 +1,4 @@
-package com.dataStructures;
+package com.datastructures;
 
 import java.io.Serializable;
 import java.util.EmptyStackException;

src/main/java/com/matchings/stablematching/GaleShapley.java

@@ -1,4 +1,4 @@
-package com.matchings.stableMatching;
+package com.matchings.stablematching;
 
 public class GaleShapley {
 

src/test/java/com/datastructures/BinaryTreeTest.java

@@ -1,4 +1,4 @@
-package com.dataStructures;
+package com.datastructures;
 
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;

src/test/java/com/datastructures/DisjointSetTest.java

@@ -1,4 +1,4 @@
-package com.dataStructures;
+package com.datastructures;
 
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;

src/test/java/com/datastructures/GeneralQueueTest.java

@@ -1,4 +1,4 @@
-package com.dataStructures;
+package com.datastructures;
 
 
 import com.types.Queue;

src/test/java/com/datastructures/IntQueueTest.java

@@ -1,4 +1,4 @@
-package com.dataStructures;
+package com.datastructures;
 
 import static org.junit.Assert.*;
 

src/test/java/com/datastructures/SinglyLinkedListTest.java

@@ -1,4 +1,4 @@
-package com.dataStructures;
+package com.datastructures;
 
 import org.junit.Test;
 import org.junit.jupiter.api.Assertions;

src/test/java/com/datastructures/StackTest.java

@@ -1,4 +1,4 @@
-package com.dataStructures;
+package com.datastructures;
 
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;

src/test/java/com/matchings/stablematching/GaleShapleyTest.java

@@ -1,4 +1,4 @@
-package com.matchings.stableMatching;
+package com.matchings.stablematching;
 
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;