Change project structure to a Maven Java project + Refactor (#2816)

src/main/java/com/thealgorithms/strings/CharactersSame.java

@@ -0,0 +1,30 @@
+package com.thealgorithms.strings;
+
+public class CharactersSame {
+
+    /**
+     * Driver Code
+     */
+    public static void main(String[] args) {
+        assert isAllCharactersSame("");
+        assert !isAllCharactersSame("aab");
+        assert isAllCharactersSame("aaa");
+        assert isAllCharactersSame("11111");
+    }
+
+    /**
+     * check if all the characters of a string are same
+     *
+     * @param s the string to check
+     * @return {@code true} if all characters of a string are same, otherwise
+     * {@code false}
+     */
+    public static boolean isAllCharactersSame(String s) {
+        for (int i = 1, length = s.length(); i < length; ++i) {
+            if (s.charAt(i) != s.charAt(0)) {
+                return false;
+            }
+        }
+        return true;
+    }
+}