我们应该直接在Java中将参数作为变量或作为新对象传递给方法吗

Question

Consider the following two calls to the same method in java:-

1) doSomething(new Object[]{"something"}) ;

2)

Object[] obj = {"something"} ;

doSomething(obj);

Which one is more efficient in terms of memory and time efficiency ? I would say the 1) is better in both memory and time efficiency. Reason being in the second option requires us to create another variable (extra memory) and then assigns that value to the variable (extra time). Any comments ?

Just to clarify the object will be create only once, i am talking about the extra variable being used to hold the address of the newly created object.

Answer 1

Both are the same in terms of time and memory. The extra assignment can be optimized away by the compiler.

A difference is that the second version gives you an opportunity to give a useful name to your variable, which can make the code more clear.

Answer 2

The second call allows you to reuse the object in the calling method, but the first one does not.

It has no incidence on memory, as the passed object is created anyway.

Answer 3

You should always consider what is simpler and clearer first. You should only consider performance when you know you have a problem because you measured it in a profiler or micro-benchmark.

The best option is likely to be to use varargs

doSomething("something");

void doSomething(String... args) { }

Note: not only is the this simplest, but it is also potentially the fastest as the JIT can eliminate the String[] created.