| CSC300 / CSC402: Boxing [13/24] | |
Conversion from base type to object type is called boxing.
Conversion from object type to base type is called unboxing.
The base types we will use in this course are mostly int and double.
For int and double, the operations are as follows
| Base type | Object type | Boxing (base to object) | Unboxing (object to base) |
|---|---|---|---|
int base = 0; |
Integer object = null; |
object = Integer.valueOf(base); |
base = object.intValue(); |
double base = 0.0; |
Double object = null; |
object = Double.valueOf(base); |
base = object.doubleValue(); |
Java has six additional base types:
| Base type | Object type | Boxing (base to object) | Unboxing (object to base) |
|---|---|---|---|
boolean base = false; |
Boolean object = null; |
object = Boolean.valueOf(base); |
base = object.booleanValue(); |
float base = 0.0F; |
Float object = null; |
object = Float.valueOf(base); |
base = object.floatValue(); |
byte base = 0; |
Byte object = null; |
object = Byte.valueOf(base); |
base = object.byteValue(); |
char base = 0; |
Character object = null; |
object = Character.valueOf(base); |
base = object.charValue(); |
short base = 0; |
Short object = null; |
object = Short.valueOf(base); |
base = object.shortValue(); |
long base = 0L; |
Long object = null; |
object = Long.valueOf(base); |
base = object.longValue(); |