How to cast an Object to an int

java object casting integer
Sheehan Alam picture Sheehan Alam · Sep 7, 2010 · Viewed 634.8k times · Source

How can I cast an Object to an int in java?

Answer

Colin Hebert picture Colin Hebert · Sep 7, 2010

If you're sure that this object is an Integer :

int i = (Integer) object;

Or, starting from Java 7, you can equivalently write:

int i = (int) object;

Beware, it can throw a ClassCastException if your object isn't an Integer and a NullPointerException if your object is null.

This way you assume that your Object is an Integer (the wrapped int) and you unbox it into an int.

int is a primitive so it can't be stored as an Object, the only way is to have an int considered/boxed as an Integer then stored as an Object.

If your object is a String, then you can use the Integer.valueOf() method to convert it into a simple int :

int i = Integer.valueOf((String) object);

It can throw a NumberFormatException if your object isn't really a String with an integer as content.

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