R4R Java CoreJava Packages Lang

Package java. lang

Package java.lang.
Package java.lang is most fundamental package provides classes that are fundamental to the design of the Java programming language. Package contain several classes-

• Most important classes-

  •  Object- An object is an instance of a class exhibits two characteristics such as state and behavior. object is the root of the class hierarchy.
  •  Class- Class is the prototype/ blueprint from which object is create. Class is used to declare fields, constructors , and methods.
     

• Primitive data type and Wrapper classes- The primitive wrapper classes and their corresponding primitive types are:

  Primitive data type	Primitive Wrapper class
  boolean	Boolean
  byte	Byte
  short	Short
  int	Integer
  long	Long
  float	Float
  double	Double
  char	Character

   

• The class Math provides commonly used mathematical functions such as sine, cosine, and square root.

• The classes String and StringBuffer similarly provide commonly used operations on character strings.

• Class Throwable encompasses objects that may be thrown the exception by the throw statement . Subclasses of Throwable represent errors and exceptions.

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