Java-preliminary Understanding-Common Object API (basic data type Object wrapper class-Overview)

One.

There are eight basic data types: Byte,short,int,long,float,double,char,boolean. In the world of Java, everything is object. To make it easier to manipulate the basic data type values, we encapsulate them in objects, and classes that describe the basic data types are called basic data type Object wrapper classes.

There are eight basic data types, which means there are eight wrapper classes.

The class name has a first-character capitalization feature, originally Byte,short,int ... Lowercase are keywords and are now being modified.

Of the eight classes, char and interger are changed, compared to the original words.

What is the use of these object wrapper classes?

(The range of byte is -27~27-1,-128~127)

For a variable of type int, it has a larger range of values. As a variable, the two best values of its range are not quite OK, but instead of the object, it is easy to get the maximum value by calling its own solution to the maximum value.

Then again, the Boolean type must not be converted to the object type class because of the value range. An example of this is why it is used as an object class: If you convert the decimal number to a binary number, this requires the object class of type Boolean. I've also introduced how to convert decimal numbers to binary numbers, but it's cumbersome, not so simple.

Java-preliminary Understanding-Common Object API (basic data type Object wrapper class-Overview)