Detailed explanation of the difference between int and Integer in Java

  • 2020-04-01 01:44:09
  • OfStack

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. Initialization


int i = 1;

 Integer i = new Integer(1);   //(to look at integer as a class)

Int is the basic data type (procedural traces, but a useful addition to Java)

Integer is a class, an extension of int, that defines many transformation methods

Similar to: float float, double double, string string, etc.

For example, when you want to put something in an ArrayList, a HashMap, a built-in type like int, or double, you don't want to put it in, because the container is full of objects, so you need an enclosing class of these built-in types.

Each of the built-in types in Java has a corresponding override class.

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

1. Int is the basic data type;

Integer is the wrapper class of int.

3, int and Integer can represent a certain value;

Int and Integer are not interoperable because they have two different data types;

Examples:


 ArrayList al=new ArrayList();
 int n=40;
 Integer nI=new Integer(n);
 al.add(n);//Can not be
 al.add(nI);//can


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