...
The non-compliant code example accepts a value from the user without validating it. If this value is greater than 255, it will result in a wrap around. For instance, write(305) will print '1' since the lower order bits of 305 are preserved while the top 24 order bits are lost. That is, the result is remainder modulo 256 of the absolute value of the input.
Code Block | ||
---|---|---|
| ||
class console_write { public static void main(String[] args[]) { //Any input value > 255 will result in unexpected output System.out.write(args[10]); } } |
Compliant Solution
Use alternate means to output integers such as the System.out.print*
methods. Again, performing input validation is extremely critical.
Code Block | ||
---|---|---|
| ||
class console_write {
public static void main(String[] args) {
//Perform input validation
if(args[0] <= 255) {
System.out.print(args[0]);
}
else {
//handle error
}
}
}
|
References
Java I/O, Elliotte Rusty Harold