checking Symmetric Tree in java

Tree/Symmetric Tree.java

@@ -0,0 +1,31 @@
+public class TreeNode {
+      int val;
+      TreeNode left;
+      TreeNode right;
+      TreeNode() {}
+      TreeNode(int val) { this.val = val; }
+      TreeNode(int val, TreeNode left, TreeNode right) {
+          this.val = val;
+          this.left = left;
+          this.right = right;
+      }
+  }
+
+class Solution {
+    public boolean isSymmetric(TreeNode root) {
+            return dfs(root,root);
+
+    }
+
+        private boolean dfs(TreeNode r1,TreeNode r2)
+        {
+                if(r1==null && r2==null) 
+                        return true;
+                if(r1==null || r2==null) 
+                        return false;
+
+              boolean  k= (r1.val==r2.val) && dfs(r1.left,r2.right) && dfs(r1.right,r2.left);
+                return k;
+        }
+}
+