diff --git a/README.md b/README.md
index 2bf93af3..59a12807 100644
--- a/README.md
+++ b/README.md
@@ -426,7 +426,7 @@ LeetCode
|139|[Word Break](https://leetcode.com/problems/word-break/)| [C++](./algorithms/cpp/wordBreak/wordBreak.cpp)|Medium|
|138|[Copy List with Random Pointer](https://leetcode.com/problems/copy-list-with-random-pointer/)| [C++](./algorithms/cpp/copyListWithRandomPointer/copyListWithRandomPointer.cpp), [Python](./algorithms/python/CopyListWithRandomPointer/copyRandomList.py)|Hard|
|137|[Single Number II](https://leetcode.com/problems/single-number-ii/)| [C++](./algorithms/cpp/singleNumber/singleNumber.II.cpp), [Python](./algorithms/python/SingleNumberII/SingleNumberII.py)|Medium|
-|136|[Single Number](https://leetcode.com/problems/single-number/)| [C++](./algorithms/cpp/singleNumber/singleNumber.cpp)|Medium|
+|136|[Single Number](https://leetcode.com/problems/single-number/)| [C++](./algorithms/cpp/singleNumber/singleNumber.cpp), [Java](./algorithms/java/src/SingleNumber/SingleNumber.java)|Medium|
|135|[Candy](https://leetcode.com/problems/candy/)| [C++](./algorithms/cpp/candy/candy.cpp)|Hard|
|134|[Gas Station](https://leetcode.com/problems/gas-station/)| [C++](./algorithms/cpp/gasStation/gasStation.cpp)|Medium|
|133|[Clone Graph](https://leetcode.com/problems/clone-graph/)| [C++](./algorithms/cpp/cloneGraph/cloneGraph.cpp)|Medium|
@@ -496,7 +496,7 @@ LeetCode
|69|[Sqrt(x)](https://leetcode.com/problems/sqrtx/)| [C++](./algorithms/cpp/sqrt/sqrt.cpp)|Medium|
|68|[Text Justification](https://leetcode.com/problems/text-justification/)| [C++](./algorithms/cpp/textJustification/textJustification.cpp)|Hard|
|67|[Add Binary](https://leetcode.com/problems/add-binary/)| [C++](./algorithms/cpp/addBinary/addBinary.cpp)|Easy|
-|66|[Plus One](https://leetcode.com/problems/plus-one/)| [C++](./algorithms/cpp/plusOne/plusOne.cpp)|Easy|
+|66|[Plus One](https://leetcode.com/problems/plus-one/)| [C++](./algorithms/cpp/plusOne/plusOne.cpp) [Java](./algorithms/java/src/PlusOne/PlusOne.java)|Easy|
|65|[Valid Number](https://leetcode.com/problems/valid-number/)| [C++](./algorithms/cpp/validNumber/validNumber.cpp)|Easy|
|64|[Minimum Path Sum](https://leetcode.com/problems/minimum-path-sum/)| [C++](./algorithms/cpp/minimumPathSum/minimumPathSum.cpp), [Java](./algorithms/java/src/dynamicProgramming/minimumPathSum/minimumPathSum.java)|Medium|
|63|[Unique Paths II](https://leetcode.com/problems/unique-paths-ii/)| [C++](./algorithms/cpp/uniquePaths/uniquePaths.II.cpp), [Java](./algorithms/java/src/dynamicProgramming/uniquePaths/uniquePathsII.java)|Medium|
diff --git a/algorithms/java/src/PlusOne/PlusOne.java b/algorithms/java/src/PlusOne/PlusOne.java
new file mode 100644
index 00000000..ef9289b9
--- /dev/null
+++ b/algorithms/java/src/PlusOne/PlusOne.java
@@ -0,0 +1,32 @@
+// Source : https://leetcode.com/problems/plus-one/description/
+// Author : Anas Mak
+// Date : 2023-01-26
+
+/**********************************************************************************
+ * You are given a large integer represented as an integer array digits,
+ * where each digits[i] is the ith digit of the integer.
+ * The digits are ordered from most significant to least significant in left-to-right order.
+ * The large integer does not contain any leading 0's.
+ * Increment the large integer by one and return the resulting array of digits.
+ **********************************************************************************/
+
+package Solution;
+
+ class Solution {
+ public int[] plusOne(int[] digits) {
+ for(int i = digits.length - 1 ; i >=0 ; i--){
+ if(digits[i] != 9){
+ digits[i]+=1;
+ return digits;
+ }
+
+ else{
+ digits[i] = 0;
+ }
+ }
+
+ int[] array = new int[digits.length + 1];
+ array[0] = 1;
+ return array;
+ }
+}
\ No newline at end of file
diff --git a/algorithms/java/src/PlusOne/PlusOneTest.java b/algorithms/java/src/PlusOne/PlusOneTest.java
new file mode 100644
index 00000000..e3dd6173
--- /dev/null
+++ b/algorithms/java/src/PlusOne/PlusOneTest.java
@@ -0,0 +1,21 @@
+package Solution;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Test for 66. Plus One
+ */
+public class PlusOne {
+ @Test
+ public void test() {
+ Solution solution = new Solution();
+ int[] array1 = [4,3,2,1];
+ Assert.assertTrue(solution.PlusOne(array1) == [4,3,2,2]);
+ int[] array2 = [1,2,3];
+ Assert.assertTrue(solution.SingleNumber(array2) == [1,2,4]);
+ int[] array3 = [9];
+ Assert.assertTrue(solution.SingleNumber(array3) == [1,0]);
+
+ }
+}
diff --git a/algorithms/java/src/SingleNumber/SingleNumber.java b/algorithms/java/src/SingleNumber/SingleNumber.java
new file mode 100644
index 00000000..592d3da0
--- /dev/null
+++ b/algorithms/java/src/SingleNumber/SingleNumber.java
@@ -0,0 +1,50 @@
+// Source : https://leetcode.com/problems/single-number/description/
+// Author : Anas Mak
+// Date : 2023-01-25
+
+/**********************************************************************************
+ Given a non-empty array of integers nums, every element appears twice except for one.
+ Find that single one.
+
+ You must implement a solution with a linear runtime complexity and
+ use only constant extra space.
+
+ Here are few examples.
+ Example 1:
+
+ Input: nums = [2,2,1]
+ Output: 1
+ Example 2:
+
+ Input: nums = [4,1,2,1,2]
+ Output: 4
+ Example 3:
+
+ Input: nums = [1]
+ Output: 1
+
+ *
+ **********************************************************************************/
+package Solution;
+
+ class Solution {
+ public int singleNumber(int[] nums) {
+
+ Set <Integer> single = new HashSet <> ();
+ for(int i : nums){
+ if(!single.contains(i)){
+ single.add(i);
+ }
+
+ else{
+ single.remove(i);
+ }
+ }
+
+ for(int result : single){
+ return result;
+ }
+
+ return -1;
+ }
+}
\ No newline at end of file
diff --git a/algorithms/java/src/SingleNumber/SingleNumberTest.java b/algorithms/java/src/SingleNumber/SingleNumberTest.java
new file mode 100644
index 00000000..bdd0cada
--- /dev/null
+++ b/algorithms/java/src/SingleNumber/SingleNumberTest.java
@@ -0,0 +1,21 @@
+package Solution;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Test for 136. Single Number
+ */
+public class SingleNumber {
+ @Test
+ public void test() {
+ Solution solution = new Solution();
+ int[] array1 = [2,2,1];
+ Assert.assertTrue(solution.SingleNumber(array1) == 1);
+ int[] array2 = [4,1,2,1,2];
+ Assert.assertTrue(solution.SingleNumber(array2) == 4);
+ int[] array3 = [1];
+ Assert.assertTrue(solution.SingleNumber(array3) == 1);
+
+ }
+}