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| Summary: | Unnecessary test for null | ||
|---|---|---|---|
| Product: | java | Reporter: | zgabi |
| Component: | Hints | Assignee: | Svata Dedic <sdedic> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | jo.navy, rosa_t |
| Priority: | P3 | ||
| Version: | 8.0.1 | ||
| Hardware: | PC | ||
| OS: | Windows 8 x64 | ||
| Issue Type: | DEFECT | Exception Reporter: | |
| Bug Depends on: | 249320 | ||
| Bug Blocks: | |||
reprducible The same error occures for the following code
public void aFunction (Object a, Object b) {
if (a == null ? b == null : b != null) {
return;
}
if (a == null) { // unnecessary test for null appears here
// do something
}
}
If a is null and b not, the first test is false and the second is necessary.
If I rewrite the first test as
if ((a == null && b == null) || (a != null && b != null)) {
The warning disappears but the value of a is tested twice
*** Bug 251969 has been marked as a duplicate of this bug. *** *** Bug 247446 has been marked as a duplicate of this bug. *** The case in the original description is not possible to solve with the current algoritm. The 2nd case could be fixed though. Fixed in the experimental impl; wait for the umbrella issue to close. |
"Unnecessary test for null" hint is shown for the following code (at "a != null"): public void xxx(long[] a, long[] b) { if ((a == null) ^ (b == null)) { throw new Error("a and b should be both null or not null."); } if (a != null && a.length != b.length) { throw new Error("a.length != b.length"); } }