1. Definition
assert is a commonly used debugging method. To check Boolean expressions, a correct program must ensure that the value of the expression is true; if it is false, the program is in an incorrect state, and the assert will give a warning or exit.
Second, the format
(1) assert [ boolean expression]
- If [boolean expression] is true, the program continues to execute.
- If it is false, the program throws AssertionError and terminates execution.
(2) assert [ boolean expression: error expression (log)]
- If [boolean expression] is true, the program continues to execute.
- If false, the program throws java.lang.AssertionError and outputs [error message]
3. Open
The default assert (assert) in IDEA is off, set jvm
the parameters, the parameters are -enableassertions
or -ea
(recommended).