ArcticLord ArcticLord - 4 months ago 6
Java Question

Whats the purpose of the primitive getter/setter in Field?

In the documentation for

public Object get(Object obj)
method in the
class it is stated that

The value is automatically wrapped in an object if it has a primitive

and for
public void set(Object obj, Object value)

If the underlying field is of a primitive type, an unwrapping
conversion is attempted to convert the new value to a value of a
primitive type.

So am I right that the only purpose of the specific primitive getter and setter like
is to prevent a redundant type conversion?

Since this code works fine

public class Test{
int i = 1;
public static void main(String[] args) throws Exception{
Test inst = new Test();
Class<?> clazz = inst.getClass();
Field fi = clazz.getDeclaredField("i");
int ii = (int) fi.get(inst);
Integer iii = new Integer(ii * 2);
fi.set(inst, iii);

I am asking if someone knows a scenario that needs you to use these methods aside from performance reasons.


It's for both type-safety and efficiency. Think about it the other way - the get*() methos are the intended way to access primitive fields, and doing so via get() just happens to work as well but requires boxing/unboxing.

In other words the only reason to use get() on a primitive field is if you don't know its type ahead of time.