Convert primitive type to string in java

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COMPLETE SOURCE CODE FOR : ConvertPrimitiveTypeToString.java
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public class ConvertPrimitiveTypeToString
{
public static void main(String[]args)
{
 //boolean
 String a=String.valueOf(true);
 System.out.println("boolean : "+a);

 //byte
 a=String.valueOf((byte)9);
 System.out.println("byte : "+a);

 //char
 a=String.valueOf('a');
 System.out.println("char : "+a);

 //short
 a=String.valueOf((short)9);
 System.out.println("short : "+a);

 //int
 a=String.valueOf(9);
 System.out.println("int : "+a);

 //long
 a=String.valueOf(9L);
 System.out.println("long : "+a);

 //float
 a=String.valueOf(9.0F);
 System.out.println("float : "+a);

 //double
 a=String.valueOf(9.0D);
 System.out.println("double : "+a);
}
}

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Convert uppercase to lowercase in java

Source code below will convert uppercase(HELLO WORLD) to lowercase(hello world)

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COMPLETE SOURCE CODE FOR : ConvertUppercaseToLowercase.java
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public class ConvertUppercaseToLowercase
{
public static void main(String[]args)
{
 String a="HELLO WORLD";
  
    //CONVERT HELLO WORLD TO hello world
    String b=a.toLowerCase();
    a=b;
    System.out.println(a);
}
}

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Convert lowercase to uppercase in java

Source code below will convert lowercase (hello world) to uppercase (HELLO WORLD)

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COMPLETE SOURCE CODE FOR : ConvertLowerCaseToUpperCase.java
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public class ConvertLowerCaseToUpperCase
{
public static void main(String[]args)
{
 String a="hello world";

 //CONVERT hello world TO HELLO WORLD
 String b=a.toUpperCase();
 System.out.println(b);
}
}

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Replace word in a sentence using java

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COMPLETE SOURCE CODE FOR : ReplaceAWordInASentence.java
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public class ReplaceAWordInASentence
{
public static void main(String[]args)
{
 String a="Hello World";

 //REPLACE Hello WITH Hi
 String b=a.replaceAll("Hello","Hi");
 a=b;
 System.out.println(a);

 //REPLACE World WITH Dude
 b=a.replaceAll("World","Dude");
 a=b;
 System.out.println(a);
}
}

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Replace character in a sentence in java

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COMPLETE SOURCE CODE FOR : ReplaceCharacterInASentence.java
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public class ReplaceCharacterInASentence
{
public static void main(String[]args)
{
 String a="Hellooo Woooorld";

 //REPLACE ALL CHARACTER o WITH a
 String b=a.replace('o','a');
 System.out.println(b);



 //REPLACE A CHARACTER
 //REPLACE LAST o IN Hellooo WITH a

 //IF YOU WANT TO REPLACE A CHARACTER, YOU MUST TAKE WORD
 //THAT CONTAIN THE CHARACTER AND MAKE SURE
 //THE WORD IS ONLY UNIQUE THAT CAN REPRESENT WORD
 //CONTAIN THE CHARACTER
 //This is why we take looo instead of ooo because
 //ooo also exist in Woooorld
 String c=a.replace("looo","looa");
 System.out.println(c);
}
}

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Search character or word in a sentence using java

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COMPLETE SOURCE CODE FOR : SearchCharacterOrWordInASentence.java
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public class SearchCharacterOrWordInASentence
{
public static void main(String[]args)
{
 //-1 mean the word or character that you search not exist

 String a="Hello World !!!";

 //SEARCH CHARACTER
 int b=a.indexOf('H');
 if(b!=-1)
 {
  System.out.println("H exist");
 }

 //SEARCH Hello IN Hello World !!!
 int c=a.indexOf("Hello");
 if(c!=-1)
 {
  System.out.println("Hello exist");
 }
}
}

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Get word from a sentence in java

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COMPLETE SOURCE CODE FOR : GetWordFromASentence.java
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public class GetWordFromASentence
{
public static void main(String[]args)
{
 //This source code will show you how to get word Hello from sentence Hello World

 //You can use method substring(index_for_first_letter_for_word,index_for_last_letter_plus_one)

 //Index start with 0

 //Blank space also count.In this case, space between Hello and world take 5 for it's index

 String a="Hello world!!";
 String b=a.substring(0,5);

 System.out.println(b);
}
}

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