> For the complete documentation index, see [llms.txt](https://heunnajo.gitbook.io/java/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://heunnajo.gitbook.io/java/java.lang-package-and-useful-class/wrapper-class.md). # Wrapper class \- The class wraps primitive type.\ \- When handle 8 types of primitive type as object. =>why? OOP is Object-Oriented Programming. It needs to be as Object. 90% is Object and remains are primitive type because of performance. ```java public final class Integer extends Number implements Comparable { ... private int value;//wraps int type. } ``` | primitive type | wrapper class | constructor | example | | -------------- | ------------- | ------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- | | boolean | Boolean |

Boolean(boolean value)

Boolean(String s)

|

Boolean b = new Boolean(true);

Boolean b2 = new Boolean("true");

| | char | **Character** | Character(char value) | Character c = new Character('a'); | | byte | Byte |

Byte(byte value)

Byte(String s)

|

Byte b = new Byte(10);

Byte b2 = newByte("10");

| | short | Short |

Short(short value)

Short(String s)

|

Short s = new Short(10);

Short s2 = new Short("10");

| | int | **Integer** |

Integer(int value)

Integer(String s)

|

Integer i = new Integer(100);

Integer i2 = new Integer("100");

| | long | Long |

Long(long value)

Long(String s)

|

Long l = new Long(100);

Long l2 = new Long("100");

| | float | Float |

Float(double value)

Float(float value)

Float(String s)

|

Float f = new Float(1.0);
Float f = new Float(1.0f);
Float f = new Float("1.0f");

| | double | Double |

Double(double value)

Double(String s)

|

Double d = new Double(1.0);

Double d = new Double("1.0");

| ```java Integer i = new Integer(100);//address : 0x100 Integer i2 = new Integer(100);//address : 0x200 System.out.prinln("i==i2?" + (i==i2));//false.0x100!=0x200 System.out.prinln("i.equals(i2)?" + i.equals(i2));//true.means overriding. //오른쪽 값이 더 작으면 양수,오른쪽 값이 더 크면 음수, 같으면 0 System.out.prinln("i.compareTo(i2) ="+i.compareTo(i2)); System.out.prinln("i.toString()="+i.toString()); ```