Difference between revisions of "Autoboxing"
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| − | == | + | == Wrapper Classes == |
* Wrapper classes for primtives are a mechanism to include primitives in activities reserved for objects. e.g. being part of Collections. | * Wrapper classes for primtives are a mechanism to include primitives in activities reserved for objects. e.g. being part of Collections. | ||
* Wrapper objects are '''immutable''' ! | * Wrapper objects are '''immutable''' ! | ||
| − | + | * All have two constructors - one takes a primitive, other a string representation. | |
| − | + | * A valueOf() method also takes a string and returns a wrapper object in return. | |
| + | * Wrapper to primitive - use the xxxValue() methods like intValue() and floatValue() | ||
| + | * String to primitive - e.g. Integer.parseInt("22"), Double.parseDouble("3.14"); | ||
| + | * toString() returns the string representation of a primitive. | ||
[[Category:OCPJP]] | [[Category:OCPJP]] | ||
Revision as of 02:10, 13 August 2011
Wrapper Classes
- Wrapper classes for primtives are a mechanism to include primitives in activities reserved for objects. e.g. being part of Collections.
- Wrapper objects are immutable !
- All have two constructors - one takes a primitive, other a string representation.
- A valueOf() method also takes a string and returns a wrapper object in return.
- Wrapper to primitive - use the xxxValue() methods like intValue() and floatValue()
- String to primitive - e.g. Integer.parseInt("22"), Double.parseDouble("3.14");
- toString() returns the string representation of a primitive.
