A primitive wrapper class in the Java and ActionScript programming languages is one of eight classes provided in the
java.lang package to provide object methods for the eight primitive types. All of the primitive wrapper classes in Java are immutable. J2SE 5.0 introduced autoboxing of primitive types into their wrapper object, and automatic unboxing of the wrapper objects into their primitive value—the implicit conversion between the wrapper objects and primitive values.
Wrapper classes are used to represent primitive values when an
Object is required. The wrapper classes are used extensively with
Collection classes in the
java.util package and with the classes in the
java.lang.reflect reflection package.
The primitive wrapper classes and their corresponding primitive types are:
Primitive type Wrapper class Constructor Arguments
Double wrapper classes are all subclasses of the
The wrapper classes
BigInteger are not one of the primitive wrapper classes and are mutable.
... With Java 5.0, additional wrapper classes were introduced in the java.util.concurrent.atomic package ... classes are mutable and cannot be used as a replacement for the regular wrapper classes ... The atomic wrapper classes and their corresponding types are Primitive type Wrapper class int AtomicInteger long AtomicLong boolean AtomicBoolean V AtomicReference The AtomicInteger and AtomicLong ...