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| CodeSonar® 9.0p0 Hot Tips | CONFIDENTIAL | CodeSecure Inc |
Identify useless constructions of objects.
An object is created and not assigned, and its construction has no side-effects other than on the object itself.
Java allows a few expressions to be used as commands. Among them, object creation is allowed to be used as a command since it can in principle induce side-effects and hence have a computational sense. However, creation of objects that do not induce side-effects is useless and should be removed from the code; it might actually be the sign of a programming error.
| Class Name | Unused Object (Java) | |||
|---|---|---|---|---|
| Significance | reliability | |||
| Mnemonic | JAVA.STRUCT.UUOBJ | |||
| 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="Unused Object (Java)" |
Japanese (ja)
public class Creations {
public static boolean unnamed;
public static void main(String[] args) {
Test test = new Test(args.length > 0 ? args[0] : null); // ok: object assigned to a local variable
new Test("hello"); // "Unused Object (Java)" warning issued here
new Test(); // ok: constructor has side effect on field 'unnamed'
System.out.println(test);
}
private static class Test {
private final String name;
private Test(String name) {
this.name = name;
}
private Test() {
this.name = "no name";
unnamed = true;
}
@Override
public String toString() {
return name;
}
}
}
Check if the object creation was meant to have some side-effect and delete it.
The following configuration file parameters affect checks for this warning class.