Integer vs int

int is a primitive. Integer is an object.

A primitive data type uses a small amount of memory to represent a single item of data. For example, primitive type int represents integers using 32 bits. There are only eight primitive data types in Java:

1. byte
2. char
3. boolean
4. short
5. int
6. long
7. float
8. double

Make it stick: java 8 primitives (Be Careful, Bears Shouldn't Ingest Large Furry Dogs).

Object on the other hand is a large chunk of memory that can potentially contain a great deal of data along with methods.

so for example if u say :

Integer anIntegerObject = new Integer(2); // an integer object with the value of 2

// because anIntegerObject is of type "Integer" you can call methods in the Integer Class http://docs.oracle.com/javase/7/docs/api/java/lang/Integer.html on it.

System.out.println(anIntegerObject.MAX_VALUE); // returns the maximum value an int can take = 2147483647 System.out.println(anIntegerObject.MIN_VALUE); // returns the minimum value an int can take = -2147483648 System.out.println(anIntegerObject.floatValue()); // returns the float of 2 which is = 2.0;

now if u do this :

int intPrimitive = 10;

and try to call methods in the Integer Class api on it. u will get an error

System.out.println(intPrimitive.MAX_VALUE); // Oh! Oh! can't do this.

why? the intPrimitive is like a remote control without any buttons (methods) on it!

Hey Kevin,

Integer, like Luksy already said is an object and it is also a wrapper class. The wrapper class gives primitive types methods, they can invoke (because primitives are not objects - you can't invoke methods on them). All primitive types have there wrapper classes

PRIMITIV WRAPPER boolean Boolean
byte Byte
char Character
int Integer
float Float
double Double
long Long
short Short

You see the differenece. The wrapper is uppercased and you write the whole word.

 int x = 10;
//so x is a primitive data type without methods like byteValue(), intValue() etc.

Integer someIntegerObject = new Integer(10);
//but someIntegerObject is a object with all funny methods you need to play with numbers and more

You can´t code:

System.out.println(x. byteValue());
//the compiler can´t find any method for x, but you can code

System.out.println(someIntegerObject. byteValue());
//the compiler knows that someIntegerObject is an object with method byteValue() and uses it

See this link for more information:

http://www.w3resource.com/java-tutorial/java-wrapper-classes.php

Grigorij

When u care so much about performance, be stingy with object creation!

pls refer to this link http://stackoverflow.com/questions/239560/when-should-i-use-primitives-instead-of-wrapping-objects