java--Common classes (basic type Data wrapper class)

"Packaging Class"

wrapper classes (such as Integer, double, and so on) encapsulate a corresponding numeric value of the underlying data type and give it a series of actions.  For example, the Java.lang.Integer class provides the following construction methods:Integer (int value)Integer (String s) "Common Methods"  "Program Analysis" note:<1> is allocated on the stack for int i=100, and for integer i = new Integer (100) in the heap. <2> attention to exception capture and handling is essential.        

java--Common classes (basic type Data wrapper class)