Weird test case stuck: right answer in eclipse, wrong output in OJ

• ``````public static int maxLeafPath = Integer.MIN_VALUE;
public int maxPathSum(TreeNode root) {
if(root == null) return 0;
int rst = root.val;
int maxLeft, maxRight;
if((maxLeft = maxLeaf(root.left)) > 0) rst += maxLeft;
if((maxRight = maxLeaf(root.right)) > 0) rst += maxRight;
return Math.max(rst, maxLeafPath);
}

int maxLeaf(TreeNode root){
if(root == null) return 0;
int subPath = root.val;
int maxLeft, maxRight;
if((maxLeft = maxLeaf(root.left)) > 0) subPath += maxLeft;
if((maxRight = maxLeaf(root.right)) > 0) subPath += maxRight;
if(subPath > maxLeafPath) maxLeafPath = subPath;
return Math.max(maxLeft, maxRight) <= 0 ? root.val : root.val + Math.max(maxLeft, maxRight);
}
``````

Input: {-2,1}
Output: 2
Expected: 1

When the test case is {-2, 1}, I got the right answer in eclipse, that's 1. However, it outputs 2 in OJ.
I carefully checked my code for a couple of times, and I am pretty sure it is correct.

I don't know what's wrong with it. Is it possible that I can't use global variable such as
"public static int maxLeafPath = Integer.MIN_VALUE;" in online judge?

Could anyone help me figure out this puzzling problem?