JAVA PLEASE. What I have is not working.

Integer userNumber is read from input. Write a while loop that iterates until userNumber is negative. At each iteration: - Update integer finalVal as follows: - If userNumber is odd, add userNumber to finalVal. - Otherwise, subtract userNumber from finalVal. - Then, read an integer from input into variable userNumber. Final value is 1 Note: x%2==0 returns true if x is even