# Asserting
# Checking arithmetic with assert
a = 1 - Math.abs(1 - a % 2);
// This will throw an error if my arithmetic above is wrong.
assert a >= 0 && a <= 1 : "Calculated value of " + a + " is outside of expected bounds";
return a;
# Syntax
- assert expression1;
- assert expression1 : expression2;
# Parameters
| Parameter | Details |
|---|---|
| expression1 | The assertion statement throws an AssertionError if this expression evaluates to false. |
| expression2 | Optional. When used, AssertionErrors thrown by the assert statement have this message. |
# Remarks
By default, assertions are disabled at runtime.
To enable assertions, you must run java with -ea flag.
java -ea com.example.AssertionExample
Assertions are statements that will throw an error if their expression evaluates to false. Assertions should only be used to test code; they should never be used in production.