Question

queryParms.add(new Long(empRec));

I am using JDK 1.5 and using wrapped longs to a list. My Boss was yelling at me seeing this.

Is it a good approach?
Does it impact in terms of performance.
What should be alternative?

Answer 1

It is unnecessary to do this. Java does it automatically with autoboxing.

In short – collections don’t accept primitives. So whenever you call collection.add(longVar) it is automatically translated to collection.add(Long.valueOf(longVar))

Another thing – don’t use the constructor new Long(..) even in cases where autoboxing doesn’t work. Use Long.valueOf(..) – it first looks in a cache of Long instances. From the documentation of Long.valueOf(..):

If a new Long instance is not required, this method should generally be used in preference to the constructor Long(long), as this method is likely to yield significantly better space and time performance by caching frequently requested values.