How do I write: "get a random number between - 10 and 11 but it cannot be 0"? (java)

generate a random number in a known range and map the result to the range you want

Explanation:

Use any of the usual methods to get a random number in the range 0-20, then subtract 9. Use an IF statement to test if the result is 0. If it is, replace the value with - 10.