Use Objects.hash() or own hashCode() implementation?

Question

I have recently discovered the Objects.hash() method.

My first thought was, that this tidies up your hashCode() implementation a lot. See the following example:

@Override //traditional public int hashCode() {     int hash = 5;     hash = 67 * hash + (int)(this.id ^ (this.id >>> 32));     hash = 67 * hash + (int)(this.timestamp ^ (this.timestamp >>> 32));     hash = 67 * hash + Objects.hashCode(this.severity);     hash = 67 * hash + Objects.hashCode(this.thread);     hash = 67 * hash + Objects.hashCode(this.classPath);     hash = 67 * hash + Objects.hashCode(this.message);     return hash; }  @Override //lazy public int hashCode() {     return Objects.hash(id, timestamp, severity, thread, classPath, message); } 

Although I have to say that this seems too good to be true. Also I've never seen this usage.

Are there any downsides of using Objects.hash() compared to implementing your own hash code? When would I choose each of those approaches?

Update

Although this topic is marked as resolved, feel free to keep posting answers that provide new information and concerns.

Answer 1

Note that the parameter of Objects.hash is Object.... This has two main consequences:

• Primitive values used in the hash code calculation have to be boxed, e.g. this.id is converted from long to Long.
• An Object[] has to be created to invoke the method.

The cost of creating of these "unnecessary" objects may add up if hashCode is called frequently.