How to test whether the value of a Java field gotten by reflection is null?

Question

I have

Field f = this.getClass().getFields()[0];

I need to know if f's value in this is null or not. There are many methods like getInt() and getDouble(), but I have not found a method like Object getData() or isNull(). Is there such a method?

Solution 1

field.get(target) returns Object. So you can checkif (field.get(this) == null) {..}

If the field is primitive, it will get wrapped. int -> Integer, char -> Character, etc.

Solution 2

You need to get the field from the object then check if it is null

Field f = this.getClass().getFields()[0];
if (f.get(this) == null)
  ...

Comments

[shift66]

and what if it has a primitive type?

[Nom1fan]

@stevemoretz No need to swear. target is the object the field belongs to. For example: SomeClass object = new SomeClass(); Field field = object.getDelcaredField("fieldName"); field.get(object); So in this case object is the target Bozho meant above.

[Steve Moretz]

@Nom1fan That actually was a long time ago.I figured it out myself but anyway thanks.And that really wasn't a swear.sorry anyway.