About assertion

[Jack Lau]

Hello All,

I do not understand why the following answer is correct?
Q: Given an assert statement - assert exp1 : exp2;
A: Whenever assertions are enabled, exp1 always get evaluated

So I write a program to test it.

  
public class TestAssert {

public static boolean m() {
boolean b1 = true;
boolean b2 = false;
 
System.out.println("call m() ... ");
return (b1 == b2);
}

public static void main(String[] args) {

assert m() : "b1 != b2";
System.out.println("No AssertionError");
}
}

I run the above program with "java -ea -cp . TestAssert", it prints "AssertionError: b != b2"
However, I use "java -cp . TestAssert", it only prints "No AssertionError" but without "call me() ..." ?

Is the anwser wrong ?

Thanks in advance!!
Jack

[Geoffrey Vlassaks]

Assertions are disabled by default. You have to enable them by yourself (fe. using -ea). So for the second run statement, all the "assert" code will be skipped..

Greetz

[Jack Lau]

Thanks!

Jack