Asserting

Versions

[{“Name”:“Java SE 1.4”,“GroupName”:null},{“Name”:“Java SE 5”,“GroupName”:null},{“Name”:“Java SE 6”,“GroupName”:null},{“Name”:“Java SE 7”,“GroupName”:null},{“Name”:“Java SE 8”,“GroupName”:null},{“Name”:“Java SE 9 (Early Access)”,“GroupName”:null}]

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.