Detailed explanation of the difference between int and Integer in Java

Author：Eve Cole Update Time：2024-11-18 15:06:01

1. Data types in Java are divided into basic data types and complex data types.

int is the former, and integer is the latter (that is, a class).

2. During initialization

Copy the code code as follows:

int i = 1;

Integer i = new Integer(1); // (treat integer as a class)

int is the basic data type (a trace left by the process orientation, but a useful supplement to Java)

Integer is a class, an extension of int, and defines many conversion methods.

Similar ones include: float Float, double Double, string String, etc.

For example: when you need to put things into ArrayList or HashMap, built-in types such as int and double cannot be put in, because the containers hold objects. This requires outer covering classes of these built-in types. .

Every built-in type in Java has a corresponding covering class.

The relationship between int and Integer in Java is relatively subtle. The relationship is as follows:

1. int is the basic data type;

2. Integer is the encapsulation class of int;

3. Both int and Integer can represent a certain value;

4. Int and Integer cannot be used interchangeably because they are two different data types;

Example:

Copy the code code as follows:

ArrayList al=new ArrayList();
int n=40;
Integer nI=new Integer(n);
al.add(n);//Not possible
al.add(nI);//Yes