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      Course
      Number Class

      Java Tutorial

      This Java tutorial is tailored for newcomers, offering a journey from basic principles to complex Java programming techniques. Completing this tutorial equips you with a solid understanding of Java, preparing you for advanced learning. You'll emerge ready to tackle the challenges of becoming a top-tier software engineer, with the skills to innovate and excel in the vast world of software development.

      Number Class

      Normally, when we work with Numbers, we use primitive data types such as byte, int, long, double, etc.
      Consider the below example:
      int i = 5000;
      float gpa = 13.65f;
      double mask = 125;
      Sometimes, there may be some situations where we need to use objects instead of primitive data types. To achieve this, Java provides wrapper classes.
      All the wrapper classes (Integer, Long, Byte, Double, Float, Short) are subclasses of the abstract class Number.

      Java Number Class

      The Number class is an abstract class in java.lang package. It is the superclass of the classes that represent numeric values convertible to primitive data types such as byte, short, int, long, float, and double.
      
      The object of the wrapper class contains or wraps its respective primitive data type. Converting primitive data types into object is called boxing, and this is taken care by the compiler. Therefore, while using a wrapper class you just need to pass the value of the primitive data type to the constructor of the Wrapper class.
      And the Wrapper object will be converted back to a primitive data type, and this process is called unboxing. The Number class is part of the java.lang package.
      Following is an example of boxing and unboxing

      Example

      In this example, we've showcase use of primitives and their operations using a wrapper class. In first statement we've assigned an int to an Integer object x which is termed as boxing. In second statment, we're adding 10 to x which requires x to be unboxed as int and addition is performed and result is assigned back to the variable x and printed.
      public class Test {
      
         public static void main(String args[]) {
            Integer x = 5; // boxes int to an Integer object
            x =  x + 10;   // unboxes the Integer to a int
            System.out.println(x); 
         }
      }
      This will produce the following result

      Output

      15
      When x is assigned an integer value, the compiler boxes the integer because x is integer object. Later, x is unboxed so that they can be added as an integer.

      Java Number Class Methods

      Following is the list of the instance methods that all the subclasses of the Number class implements
      Sr.No.
      Method & Description
      1
      byteValue()
      This method returns the value of the specified number as a byte.
      2
      doubleValue()
      This method returns the value of the specified number as a double.
      3
      floatValue()
      This method returns the value of the specified number as a float.
      4
      intValue()
      This method returns the value of the specified number as a int.
      5
      longValue()
      This method returns the value of the specified number as a long.
      6
      compareTo()
      Compares this Number object to the argument.
      7
      equals()
      Determines whether this number object is equal to the argument.
      8
      valueOf()
      Returns an Integer object holding the value of the specified primitive.
      9
      toString()
      Returns a String object representing the value of a specified number.
      10
      parseInt()
      This method is used to get the primitive data type of a certain String.
      11
      abs()
      Returns the absolute value of the argument.
      12
      ceil()
      Returns the smallest integer that is greater than or equal to the argument. Returned as a double.
      13
      floor()
      Returns the largest integer that is less than or equal to the argument. Returned as a double.
      14
      rint()
      Returns the integer that is closest in value to the argument. Returned as a double.
      15
      round()
      Returns the closest long or int, as indicated by the method's return type to the argument.
      16
      min()
      Returns the smaller of the two arguments.
      17
      max()
      Returns the larger of the two arguments.
      18
      exp()
      Returns the base of the natural logarithms, e, to the power of the argument.
      19
      log()
      Returns the natural logarithm of the argument.
      20
      pow()
      Returns the value of the first argument raised to the power of the second argument.
      21
      sqrt()
      Returns the square root of the argument.
      22
      sin()
      Returns the sine of the specified double value.
      23
      cos()
      Returns the cosine of the specified double value.
      24
      tan()
      Returns the tangent of the specified double value.
      25
      asin()
      Returns the arcsine of the specified double value.
      26
      acos()
      Returns the arccosine of the specified double value.
      27
      atan()
      Returns the arctangent of the specified double value.
      28
      atan2()
      Converts rectangular coordinates (x, y) to polar coordinate (r, theta) and returns theta.
      29
      toDegrees()
      Converts the argument to degrees.
      30
      toRadians()
      Converts the argument to radians.
      31
      random()
      Returns a random number.

      Java Number: Wrapper Classes

      Following is the list of the wrapper classes that all the subclasses of the Number class
      Sr.No.
      Class & Description
      1
      Boolean
      The Java Boolean class wraps a value of the primitive type boolean in an object.
      2
      Byte
      The Java Byte class wraps a value of the primitive type byte in an object.
      3
      Character
      The Java Character class wraps a value of the primitive type char in an object.
      4
      Double
      The Java Double class wraps a value of the primitive type double in an object.
      5
      Float
      The Java Float class wraps a value of the primitive type float in an object.
      6
      Integer
      The Java Float class wraps a value of the primitive type float in an object.
      7
      Long
      The Java Long class wraps a value of the primitive type long in an object.
      8
      Short
      The Java Short class wraps a value of the primitive type short in an object.