diff --git a/climbing-stairs/sonshn.java b/climbing-stairs/sonshn.java
new file mode 100644
index 0000000000..f4df8a8c45
--- /dev/null
+++ b/climbing-stairs/sonshn.java
@@ -0,0 +1,20 @@
+/**
+ * dp[i] = dp[i - 1] + dp[i - 2]
+ */
+class Solution {
+    public int climbStairs(int n) {
+        if (n <= 2) {
+            return n;
+        }
+
+        int[] dp = new int[n + 1];
+        dp[1] = 1;
+        dp[2] = 2;
+
+        for (int i = 3; i <= n; i++) {
+            dp[i] = dp[i - 1] + dp[i - 2];
+        }
+
+        return dp[n];
+    }
+}
diff --git a/number-of-1-bits/sonshn.java b/number-of-1-bits/sonshn.java
new file mode 100644
index 0000000000..ee143ec9d4
--- /dev/null
+++ b/number-of-1-bits/sonshn.java
@@ -0,0 +1,19 @@
+/**
+ * hammingWeight
+ * 정수 n의 이진수 표현에서 1의 개수를 반환
+ * 
+ * 시간 복잡도: O(1)
+ * 공간 복잡도: O(1)
+ */
+public class sonshn {
+    public int hammingWeight(int n) {
+        int count = 0;
+
+        while (n != 0) {
+            count += (n & 1);
+            n >>>= 1;
+        }
+
+        return count;
+    }
+}
diff --git a/valid-anagram/sonshn.java b/valid-anagram/sonshn.java
new file mode 100644
index 0000000000..5f9548cf62
--- /dev/null
+++ b/valid-anagram/sonshn.java
@@ -0,0 +1,19 @@
+import java.util.*;
+
+/**
+ * String to char array, sort, and compare
+ * 
+ * 시간 복잡도: O(nlogn)
+ * 공간 복잡도: O(n)
+ */
+class Solution {
+    public boolean isAnagram(String s, String t) {
+        char[] sArray = s.toCharArray();
+        char[] tArray = t.toCharArray();
+
+        Arrays.sort(sArray);
+        Arrays.sort(tArray);
+
+        return Arrays.equals(sArray, tArray);
+    }
+}
diff --git a/valid-palindrome/sonshn.java b/valid-palindrome/sonshn.java
new file mode 100644
index 0000000000..f4f98c96c2
--- /dev/null
+++ b/valid-palindrome/sonshn.java
@@ -0,0 +1,36 @@
+/**
+ * Palindrome 문자열인지 확인하는 문제
+ * 
+ * Java에서 제공하는 Character.isLetterOrDigit() 메서드를 사용하여 알파벳과 숫자인지 확인하고,
+ * Character.toLowerCase() 메서드를 사용하여 대소문자를 구분하지 않고 비교
+ * 
+ * 시간 복잡도: O(n)
+ * 공간 복잡도: O(1)
+ */
+class Solution {
+    public boolean isPalindrome(String s) {
+        int left = 0;
+        int right = s.length() - 1;
+
+        while (left < right) {
+
+            while (left < right && !Character.isLetterOrDigit(s.charAt(left))) {
+                left++;
+            }
+
+            while (left < right && !Character.isLetterOrDigit(s.charAt(right))) {
+                right--;
+            }
+
+            if (Character.toLowerCase(s.charAt(left))
+                    != Character.toLowerCase(s.charAt(right))) {
+                return false;
+            }
+
+            left++;
+            right--;
+        }
+
+        return true;
+    }
+}