Adding A Constructor

First of all, the methods now work on their own objects, and so are no longer class methods.

public class TreeNode {
	int value;
	TreeNode left, right;

	static TreeNode tree(int v, TreeNode l, TreeNode r){
		TreeNode temp=new TreeNode();
		temp.value=v;
		temp.left=l;
		temp.right=r;
		return temp;
		}

	static int treesum(TreeNode t){
		int result;
		result=t.value;
		if(t.left!=null)result+=treesum(t.left);
		if(t.right!=null)result+=treesum(t.right);
		return result;
		}
	}