Assertions

[kalpana appala]

Hi

 
class A {
  private void m1 (int i) {
    assert i < 10 : i; System.out.print(i);
  }
  public void m2 (int i) {
    assert i < 10 : i; System.out.print(i);
  }
  public static void main (String[] args) {
    A a = new A(); a.m1(11); a.m2(12);
}}
 

For the above code one of the answers says the following is true
"The assert statements are being used to check a precondition--something that must be true when the method is invoked".
Is that statement always true??? In other words: is it a general statement?
In some other question the above statement is listed as not true.
Can someone explain the meaning of that statement and the relevance for the above code.
Thanks a bunch

[Ashok C. Mohan]

"The assert statements are being used to check a precondition--something that must be true when the method is invoked".

This is perfectly true,as far as the use of assertions is considered.But there are other conditions that has to be met for an assertion to be appropriate(Please note the word appropriate-not valid).One of these is
"Do not use assertions to validate arguments to a public method."
Which is done in your code.This is perfectly legal,but is not an appropriate way to use assertions.