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Java What is Next? In the next chapter, we will discuss about Number class (in the <strong>java</strong>.lang package) and its subclasses in Java Language. We will be looking into some of the situations where you will use instantiations of these classes rather than the primitive data types, as well as classes such as formatting, mathematical functions that you need to know about when working with Numbers. 81
11. Java – Numbers Class Java Normally, when we work with Numbers, we use primitive data types such as byte, int, long, double, etc. Example int i = 5000; float gpa = 13.65; byte mask = 0xaf; However, in development, we come across situations where we need to use objects instead of primitive data types. In order to achieve this, Java provides wrapper classes. All the wrapper classes (Integer, Long, Byte, Double, Float, Short) are subclasses of the abstract class Number. 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 <strong>java</strong>.lang package. Following is an example of boxing and unboxing: public class Test{ } public static void main(String args[]){ } Integer x = 5; // boxes int to an Integer object x = x + 10; System.out.println(x); // unboxes the Integer to a int 82
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Java About the Tutorial Java is a h
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Java 5. Java - Basic Datatypes ....
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Java Java - String Buffer delete()
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Java File Class ...................
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Java The Dictionary Class .........
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Java - Basics
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Java Distributed: Java is designe
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2. Java - Environment Setup Java In
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3. Java - Basic Syntax Java When we
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Java Java Identifiers All Java comp
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Java class const continue default d
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4. Java - Objects & Classes Java Ja
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Java Each time a new object is crea
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Java This will produce the followin
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Java Example This example explains
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Java Import Statements In Java if a
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Java Now, compile both the classes
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Java Example: short s = 10000, sho
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Java Prefix 0 is used to indicate o
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6. Java - Variable Types Java A var
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Java Example public class Test { }
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Java Parameters Here is the detail
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Java 11 void setLength(int newLengt
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Java Using String's static format()
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Java 15 int hashCode() Returns a ha
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Java 35 boolean startsWith(String p
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Java Java - String compareTo(Object
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Java } } result = str3.compareTo( s
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Java Example public class Test { }
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Java Example public class Test { pu
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Java Example public class Test{ pub
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Java Parameters Here is the detail
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Java } } }catch( Exception ex){ } S
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Java fromIndex -- the index to sta
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Java Return Value Example This met
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Java System.out.println(Str1.region
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Java Java - String replace() Method
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Java Java - String replaceFirst() M
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Java } } System.out.println(retval)
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Java } } System.out.println(retval)
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Java } } System.out.println(Str.sta
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Java Syntax Here is the syntax of t
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Java Java - String toLowerCase() Me
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Java Java - String toString() Metho
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Java Syntax Here is the syntax of t
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Java valueOf(char[] data, int
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Java The above statement does two t
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Java The foreach Loops JDK 1.5 intr
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Java public static void fill(int[]
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Java 5 int compareTo(Object obj) Op
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Java Simple DateFormat Format Codes
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Java } } // display time and date u
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Java I Two-digit hour (with leading
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Java 5 GregorianCalendar(Locale aLo
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Java void roll(int field, boolean u
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Java re? Matches 0 or 1 occurrence
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Java Methods of the Matcher Class H
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Java The start and end Methods Foll
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Java } } System.out.println("lookin
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Java PatternSyntaxException Class M
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Java Parameter List: The list of
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Java Example public class ExampleVo
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Java Example The following program
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Java } } You will need to call a co
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Java this(); } //Assigning the loca
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Java Standard Streams All the progr
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Java The two important streams are
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Java This method reads upto len num
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Java DataInputStream The DataInputS
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Java FileOutputStream FileOutputStr
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Java If you try to compile the abov
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Java } public void setAddress(Strin
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Java Inheriting the Abstract Class
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Java static void showpop(Stack st)
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Java boolean isEmpty( ) 3 Returns t
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Java Object put(Object k, Object v)
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Java Hashtable(int size, float fill
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Java @exception Adds a Throws subhe
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Java /** * This is the main method
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