J2SE 5.0 Examples---native types of autoboxing and auto-unboxing

Autoboxing and auto-unboxing of J2SE primitive types
We know that in Java, the native type such as Int,long is not a class that inherits from object, so there are many operations that we cannot use primitive type operations, such as trying to put an integer into a set, we must first create an integer object, The object is then put into the collection. When we take the number from the collection, we take out an integer object, so we can't use subtraction operator directly, but we must use Integer.intvalue () to get the corresponding value, such process called boxing and unboxing.

j2se5.0 supports autoboxing and auto-unboxing, which means that we don't have to do these boxing and unboxing operations manually anymore, and the Java language will do it for us. You can refer to the following example:

List<integer> intlist=new arraylist<integer> ();



Intlist.add (2);



Intlist.add (New Integer (5));



int I=3+intlist.get (0);//i=5



int J=3+intlist.get (1); J=8

From this procedure we can see that autoboxing and auto-unboxing have spared us a lot of unnecessary work.