Data Structures and Algorithms in Java[1].pdf - Fulvio Frisone

Calling the new operator on a class type causes three events to occur:
• A new object is dynamically allocated in memory, and all instance
variables are initialized to standard default values. The default values are null
for object variables and 0 for all base types except boolean variables (which are
false by default).
• The constructor for the new object is called with the parameters specified.
The constructor fills in meaningful values for the instance variables and performs
any additional computations that must be done to create this object.
• After the constructor returns, the new operator returns a reference (that is,
a memory address) to the newly created object. If the expression is in the form of
an assignment statement, then this address is stored in the object variable, so the
object variable refers to this newly created object.
Number Objects
We sometimes want to store numbers as objects, but base type numbers are not
themselves objects, as we have noted. To get around this obstacle, Java defines a
wrapper class for each numeric base type. We call these classes number classes.
In Table 1.2, we show the numeric base types and their corresponding number
class, along with examples of how number objects are created and accessed. Since
Java 5.0, a creation operation is performed automatically any time we pass a base
number to a method expecting a corresponding object. Likewise, the
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