JavaScript is not currently enabled, but is required for full CodeSonar manual search and browse functionality.
If you are viewing this file in your hub's Web GUI, enable JavaScript in your browser: you will also need it for GUI functionality.
If you opened this file directly from disk, your browser may be directly suppressing JavaScript functionality: certain browsers perform this suppression on local files (but not files delivered by web servers) for security reasons.
| CodeSonar® 9.0p0 Hot Tips | CONFIDENTIAL | CodeSecure Inc |
An instanceof test is always true.
This checker looks for instanceof operators that are useless, in the sense that they are always true or always false and can hence be removed from the code. This can improve the efficiency of the program. Moreover, a useless instanceof test is often the sign of a programming bug.
| Class Name | Instanceof Always True (Java) | |||
|---|---|---|---|---|
| Significance | reliability | |||
| Mnemonic | JAVA.CLASS.IOF.T | |||
| Categories |
|
|||
| Availability | Available for Java only. |
|||
| Enabling | Checks for this warning class are enabled by
default. To disable them, add the following WARNING_FILTER rule to the
project configuration file.
WARNING_FILTER += discard class="Instanceof Always True (Java)" |
Japanese (ja)
public class Main {
public static void main(String[] args) {
A a = new B();
switch ((int) (System.currentTimeMillis() % 3)) {
case 0: case 1:
a = new A(); break;
case 2:
a = new C(); break;
}
if (a instanceof C)
foo(a);
}
private static void foo(A par) {
if (par instanceof B) // "Instanceof Always True (Java)" warning issued here
System.out.println("par is a B");
}
}
public class A {}
public class B extends A {}
public class C extends B {}
In this case, the programmer should probably consider defining method foo() as foo(B par).
Check if the instanceof operator can be actually removed and that it is not the sign of an actual programming bug.
The following configuration file parameters affect checks for this warning class.