Java
Objects.hashCode() vs Objects.hash() in Java
Compare Objects.hashCode and Objects.hash, including their inputs and hashing behavior.
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| Feature / Property | Objects.hashCode(Object o) |
Objects.hash(Object... values) |
|---|---|---|
| Method type | Static utility method | Static utility method |
| Parameters | Single object (nullable) | Varargs: 0 or more objects (nullable) |
| Main purpose | Safe way to get hashCode of single object | Convenient way to compute combined hash for multiple fields |
| What it does | Returns 0 if input is null<br>Otherwise → calls o.hashCode() |
Computes combined hash code of all arguments (null → 0) |
| Null handling | Returns 0 (null-safe) | Treats each null argument as 0 (null-safe) |
| Typical usage | return Objects.hashCode(name); |
return Objects.hash(name, age, email); |
| When you override hashCode() | Use when class has only one significant field | Most common choice when class has multiple fields |
| Performance | Very fast (basically one method call + null check) | Slightly slower (due to array creation + loop)<br>But difference usually negligible |
| Introduced in | Java 7 | Java 7 |
| Recommendation | Good for single-field classes | Preferred for most real-world hashCode() implementations |