CSC300: Boxing [14/23] Previous pageContentsNext page

Conversion from base type to object type is called boxing

Conversion from object type to base type is called unboxing

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();

Many languages make an explicit distinction between object and base types

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