JAVA EE: February 2016

Java Tutorial : Java String(String pool)

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https://www.youtube.com/watch?v=hdgRaJ-G5DE&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java String(String pool)

StringTest.java

public class StringTest
{

    public static void main(String[] args)
    {
        String s1 = "Cat";
        String s2 = "Cat";
        String s3 = "Dog";
        String s4 = new String("Cat");

        System.out.println("s1 == s2 : " + (s1 == s2));
        System.out.println("s1 == s3 : " + (s1 == s3));
        System.out.println("s1 == s3 : " + (s1 == s4));
    }

}

Output

s1 == s2 : true
s1 == s3 : false
s1 == s3 : false

Click the below link to download the code:
https://sites.google.com/site/javaee4321/java/StringDemo_StringPool_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/StringDemo_StringPool_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/ae1c81370f840697c745970d52d13d8987910b41/BasicJava/StringDemo_StringPool_App/?at=master

See also:

Java Tutorial : Java String(String Constant pool)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=-NaDHpaIQX0&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java String(String Constant pool)

StringTest.java

public class StringTest
{

    public static void main(String[] args)
    {

        String s1 = "Welcome";
        String s2 = "Welcome";// will not create new instance

         System.out.println("s1 == s2 :"+(s1==s2));

    }

}

Output

s1 == s2 :true

Click the below link to download the code:
https://sites.google.com/site/javaee4321/java/StringDemo_StringConstantPool_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/StringDemo_StringConstantPool_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/ae1c81370f840697c745970d52d13d8987910b41/BasicJava/StringDemo_StringConstantPool_App/?at=master

See also:

Java Tutorial : Java String(How to create String Object)

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https://www.youtube.com/watch?v=ZYvzzTj-cJM&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java String(How to create String Object)

StringTest.java

public class StringTest
{

    public static void main(String[] args)
    {

        String greeting = "Hello world";
        System.out.println("greeting = " + greeting);

        char[] helloArray =
        { 'h', 'e', 'l', 'l', 'o', '.' };
        String helloString = new String(helloArray);
        System.out.println("helloString = " + helloString);

        String welcomeString = new String("Welcome");
        System.out.println("welcomeString = " + welcomeString);

    }

}

Output

greeting = Hello world
helloString = hello.
welcomeString = Welcome

Refer:

https://docs.oracle.com/javase/8/docs/api/index.html?java/lang/String.html

Click the below link to download the code:
https://sites.google.com/site/javaee4321/java/StringDemo_How%20to%20Create_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/StringDemo_How%20to%20Create_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/ae1c81370f840697c745970d52d13d8987910b41/BasicJava/StringDemo_How%20to%20Create_App/?at=master

See also:

Friday, 26 February 2016

Java Tutorial : Java String(What is an immutable object)

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https://www.youtube.com/watch?v=tOESavjFzxA&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java String(What is an immutable object)

Person.java

/*
 * Person is an immutable class. Person's 
 * state cannot be changed once it is created.
 * 
 * We can't subclass the final class and 
 * alter the behavior.
 */
public final class Person
{

    final String name;

    public Person(String name)
    {
        this.name = name;
    }

    public String getName()
    {
        return name;
    }

}

ImmutableTest.java

public class ImmutableTest
{

    public static void main(String[] args)
    {

        Person personObj = new Person("Peter");
        System.out.println(personObj.name);
        System.out.println(personObj.getName());

        //personObj.name = "Dave";

    }

}

Output

Peter
Peter

Click the below link to download the code:
https://sites.google.com/site/javaee4321/java/StringDemo_Immutable_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/StringDemo_Immutable_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/ec3cefb1e3f2c8e99780d56182501ac13735f589/BasicJava/StringDemo_Immutable_App/?at=master

See also:

Thursday, 25 February 2016

Java Tutorial : Java String - Playlist

Click here to watch in Youtube :
https://www.youtube.com/watch?v=2eYgQcUsCc4&list=PLmCsXDGbJHdiS7CL_7zYZD49hUr3_wdVD

See also:

Java Tutorial : Java String

Click here to watch in Youtube :
https://www.youtube.com/watch?v=2eYgQcUsCc4&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java String

Refer:

https://docs.oracle.com/javase/8/docs/api/index.html?java/lang/String.html
See also:

Java Tutorial : Java wrapper class (Character - escape sequences)

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https://www.youtube.com/watch?v=cZdmZ8W9c7k&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java wrapper class (Character - escape sequences)

EscapeSequenceTest.java

public class EscapeSequenceTest
{

    public static void main(String[] args)
    {
        System.out.println("\t he said \"Hello!\" to me.\n");
        
        System.out.println("\'Welcome\\");

    }

}

Output

     he said "Hello!" to me.

'Welcome\

Click the below link to download the code:
https://sites.google.com/site/javaee4321/java/EscapeSequenceDemo_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/EscapeSequenceDemo_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/f04fb0b510d935a99056b97ab2ac51f619fac410/BasicJava/EscapeSequenceDemo_App/?at=master

See also:

Java Tutorial : Java wrapper class (Character class methods)

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https://www.youtube.com/watch?v=-Y2au3fZtp4&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java wrapper class (Character class methods)

WrapperClassTest.java

public class WrapperClassTest
{

    public static void main(String[] args)
    {
        /*
         * Determines whether the specified char value is a
         * letter.
         */
        boolean isLetter = Character.isLetter('a');
        System.out.println("Character.isLetter('a') = " + isLetter);

        /*
         * Determines whether the specified char value is a
         * digit.
         */
        boolean isDigit = Character.isDigit('2');
        System.out.println("Character.isDigit('2')  = " + isDigit);

        /*
         * Determines whether the specified char value is
         * white space.
         */
        boolean isWhiteSpace = Character.isWhitespace(' ');
        System.out.println("Character.isWhitespace(' ')  = "
                + isWhiteSpace);

        /*
         * Determines whether the specified char value is
         * uppercase.
         */
        boolean isUpperCase = Character.isUpperCase('A');
        System.out.println("Character.isUpperCase('A')  = "
                + isUpperCase);

        /*
         * 
         * Determines whether the specified char value is
         * lowercase.
         */
        boolean isLowerCase = Character.isLowerCase('a');
        System.out.println("Character.isLowerCase('a')  = "
                + isLowerCase);

        /*
         * Returns the uppercase form of the specified char
         * value.
         */
        System.out.println("Character.toUpperCase('m') = "
                + Character.toUpperCase('m'));

        /*
         * Returns the lowercase form of the specified char
         * value.
         */
        System.out.println("Character.toLowerCase('B') = "
                + Character.toLowerCase('B'));

        /*
         * Returns a String object representing the
         * specified character value — that is, a
         * one-character string.
         */
        String str = Character.toString('u');
        System.out.println("Character.toString('u') = " + str);

    }

}

Output

Character.isLetter('a') = true
Character.isDigit('2')  = true
Character.isWhitespace(' ')  = true
Character.isUpperCase('A')  = true
Character.isLowerCase('a')  = true
Character.toUpperCase('m') = M
Character.toLowerCase('B') = b
Character.toString('u') = u

Refer:
https://docs.oracle.com/javase/8/docs/api/index.html?java/lang/Character.html

Click the below link to download the code:
https://sites.google.com/site/javaee4321/java/WrapperClassDemo_Character_methods_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/WrapperClassDemo_Character_methods_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/f04fb0b510d935a99056b97ab2ac51f619fac410/BasicJava/WrapperClassDemo_Character_methods_App/?at=master

See also:

Tuesday, 23 February 2016

Java Tutorial : Java wrapper class (Character) - Playlist

Click here to watch in Youtube :
https://www.youtube.com/watch?v=uHHb0bm0zVU&list=PLmCsXDGbJHdhob3IoIib6ro5bLVwhTu7d

See also:

Java Tutorial : Java wrapper class (Character)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=uHHb0bm0zVU&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java wrapper class (Character)

WrapperClassTest.java

public class WrapperClassTest
{

    public static void main(String[] args)
    {
        char ch = 'a';
        System.out.println("ch = " + ch);

        Character characterObj = new Character(ch);
        System.out.println("characterObj = " + characterObj);

        /*
         * If you pass a primitive char into a method that
         * expects an object, the compiler automatically
         * converts the char to a Character for you.This
         * feature is called autoboxing.
         */
        displayCharObj('c');

        /*
         * If you pass an object into a method that expects
         * an primitive char, the compiler automatically
         * converts the Character to a char for you.This
         * feature is called unboxing.
         */

        displayChar(new Character('z'));

    }

    public static void displayCharObj(Character characterObjParam)
    {
        System.out
                .println("characterObjParam = " + characterObjParam);
    }

    public static void displayChar(char chParam)
    {
        System.out.println("chParam = " + chParam);
    }
}

Output

ch = a
characterObj = a
characterObjParam = c
chParam = z

Click the below link to download the code:
https://sites.google.com/site/javaee4321/java/WrapperClassDemo_Character_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/WrapperClassDemo_Character_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/9880b82016e29094f797cfa7ceb03441b567b426/BasicJava/WrapperClassDemo_Character_App/?at=master

See also:

Java Tutorial : Java format (DecimalFormat class)

Click here to watch in Youtube :
https://www.youtube.com/watch?v=SiPUuR5UQpU&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java format (DecimalFormat class)

DecimalFormatDemo.java

import java.text.DecimalFormat;

public class DecimalFormatDemo
{

    static public void customFormat(String pattern, double value)
    {
        DecimalFormat myFormatter = new DecimalFormat(pattern);
        String output = myFormatter.format(value);
        System.out.println(value + "  " + pattern + "  " + output);
    }

    static public void main(String[] args)
    {

        customFormat("###,###.###", 123456.789);
        customFormat("###.##", 123456.789);
        customFormat("000000.000", 123.78);
        customFormat("$###,###.###", 12345.67);
    }
}

Output

123456.789  ###,###.###  123,456.789
123456.789  ###.##  123456.79
123.78  000000.000  000123.780
12345.67  $###,###.###  $12,345.67

Click the below link to download the code:
https://sites.google.com/site/javaee4321/java/FormatDemo_DecimalFormat_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/FormatDemo_DecimalFormat_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/9880b82016e29094f797cfa7ceb03441b567b426/BasicJava/FormatDemo_DecimalFormat_App/?at=master

See also:

Monday, 22 February 2016

Java Tutorial : Java format and printf methods - Playlist

Click here to watch in Youtube :
https://www.youtube.com/watch?v=B9T6PDXwXeE&list=PLmCsXDGbJHdiJdL_3JUlzdqq3xvEQ92nT

See also:

Java Tutorial : Java format and printf methods(Converters and flags)

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https://www.youtube.com/watch?v=4lyH3QaOVgA&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java format and printf methods(Converters and flags)

FormatNumericExample.java

import java.util.Calendar;
import java.util.Locale;

public class FormatNumericExample
{

    public static void main(String[] args)
    {

        long n = 461012;
        System.out.format("%d%n", n); // --> "461012"
        System.out.format("%08d%n", n); // --> "00461012"
        System.out.format("%+8d%n", n); // --> " +461012"
        System.out.format("%,8d%n", n); // --> " 461,012"
        System.out.format("%+,8d%n%n", n); // --> "+461,012"

        double pi = Math.PI;

        System.out.format("%f%n", pi); // --> "3.141593"
        System.out.format("%.3f%n", pi); // --> "3.142"
        System.out.format("%10.3f%n", pi); // -->
                                            // "     3.142"
        System.out.format("%-10.3f%n", pi); // --> "3.142"
        System.out.format(Locale.FRANCE, "%-10.4f%n%n", pi); // -->
                                                                // "3,1416"

        Calendar c = Calendar.getInstance();
        System.out.format("%tB %te, %tY%n", c, c, c); // -->
                                                        // "May 29, 2006"

        System.out.format("%tl:%tM %tp%n", c, c, c); // -->
                                                        // "2:34 am"

        System.out.format("%tD%n", c); // --> "05/29/06"

    }
}

Output

461012
00461012
 +461012
 461,012
+461,012

3.141593
3.142
     3.142
3.142     
3,1416    

February 22, 2016
12:08 pm
02/22/16

Click the below link to download the code:
https://sites.google.com/site/javaee4321/java/FormatDemo_format_Converters_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/FormatDemo_format_Converters_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/d0559102086f9677d57877fbba43556aca45fc19/BasicJava/FormatDemo_format_Converters_App/?at=master

See also:

Java Tutorial : Java format and printf methods

Click here to watch in Youtube :
https://www.youtube.com/watch?v=B9T6PDXwXeE&list=UUhwKlOVR041tngjerWxVccw

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Java Tutorial : Java format and printf methods

FormatNumericExample.java

public class FormatNumericExample
{

    public static void main(String[] args)
    {

        System.out.format("%s, %s", "Hello", "world");

        System.out.println("\n---------------------------");

        float floatVar = 90.8f;
        int intVar = 100;
        String stringVar = "Peter";

        System.out
                .format("The value of the float variable is "
                        + "%f, while the value of the integer variable is %d, "
                        + "and the string is %s", floatVar, intVar,
                        stringVar);

    }
}

Output

Hello, world
---------------------------
The value of the float variable is 90.800003, while the value of the integer variable is 100, and the string is Peter

PrintfNumericExample.java

public class PrintfNumericExample
{

    public static void main(String[] args)
    {

        System.out.printf("%s, %s", "Hello", "world");

        System.out.println("\n---------------------------");

        float floatVar = 90.8f;
        int intVar = 100;
        String stringVar = "Peter";

        System.out
                .printf("The value of the float variable is "
                        + "%f, while the value of the integer variable is %d, "
                        + "and the string is %s", floatVar, intVar,
                        stringVar);

    }
}

Output

Hello, world
---------------------------
The value of the float variable is 90.800003, while the value of the integer variable is 100, and the string is Peter

Click the below link to download the code:
https://sites.google.com/site/javaee4321/java/FormatDemo_format_App.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/FormatDemo_format_App

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/d0559102086f9677d57877fbba43556aca45fc19/BasicJava/FormatDemo_format_App/?at=master

See also: