Question w.r.t Assertions

From my understanding by reading K&B book, I can compile with code that uses "assert" as an identifier, if I use "javac -source 1.3 ..."

But when I actually compile code, I still got
==============================================
javac -source 1.3 Assert.java
Assert.java:7: warning: as of release 1.4, assert is a keyword, and may not be u
sed as an identifier
int assert = 10;
^
1 warning

Does anyone can explain it in more detail? Thanks in advance!

So whats the big deal .
You are just getting warning . I am sure , you are able to execute program . It is just for safety purpose .

Is that the first edition of K&B's book? In SDK 1.4, assert was not a keyword unless you compiled using -source 1.4. That is, -source 1.3 was effectively the default. Now under JDK 5.0, by default you get all the features of 5.0 unless you compile with -source 1.4 or -source 1.3. So now, 1.5 is the default. That means that using JDK 5.0, you can't use assert as an identifier unless you specify -source 1.3.