Java String Buffer/Builder Examples

Example : A Java program to find the length of string using Stringbuffer class method. [ length() ]

class Example
{  
     public static void main(String args[])
	{  
	int len;
	StringBuffer sb=new StringBuffer("Codershelpline");  
	len=sb.length();
	System.out.println(len); 
	}  
}  
Output :
14

Example : A Java program to find/display character at the specified position in given string using Stringbuffer class method. [ charAt() ]

class Example
{  
     public static void main(String args[])
	{	
	char ch;
	StringBuffer sb=new StringBuffer("Codershelpline");	
	ch=sb.charAt(3);
	System.out.println(ch); 
	}  
}
Output :
e

Example : A Java program to find the substring of a given string from specified beginning Index using Stringbuffer class method. [ substring() ]

class Example
{  
     public static void main(String args[])
	{  
	String Str;
	StringBuffer sb=new StringBuffer("Codershelpline");	
	Str=sb.substring(6);
	System.out.println(Str); 
	}  
}  
Output :
helpline

----------  OR  ---------
class Example
{  
     public static void main(String args[])
	{  
	String Str;
	StringBuffer sb=new StringBuffer("Codershelpline");	
	Str=sb.substring(0,6);
	System.out.println(Str); 
	}  
}  
Output :
Coders

----------  OR  ---------
class Example
{  
     public static void main(String args[])
	{  
	String Str;
	StringBuffer sb=new StringBuffer("Codershelpline");	
	Str=sb.substring(3,7);
	System.out.println(Str); 
	}  
}  
Output :
ersh

Example : A Java program to concatenate string using Stringbuffer class method. [ append() ]

class Example
{  
     public static void main(String args[])
	{  
	StringBuffer sb=new StringBuffer("Coders ");  
	sb.append("Helpline");
	System.out.println(sb); 
	}  
}  
Output :
Coders Helpline

Example : A Java program to add new string at specific position in a given string using Stringbuffer class method. [ insert() ]

class Example
{  
     public static void main(String args[])
	{  
	StringBuffer sb=new StringBuffer("Coders");  
	sb.insert(2,"Helpline");
	System.out.println(sb); 
	}  
}  
Output :
CoHelplineders

Example : A Java program to replace old string character from new string at specific position using Stringbuffer class method. [ replace() ]

class Example
{  
     public static void main(String args[])
	{  
	StringBuffer sb=new StringBuffer("Coders");  
	sb.replace(2,5,"Helpline");
	System.out.println(sb); 
	}  
}  
Output :
CoHelplines

Example : A Java program to remove/delete certain string character from a given string at specific position using Stringbuffer class method. [ delete() ]

class Example
{  
     public static void main(String args[])
	{  
	StringBuffer sb=new StringBuffer("Codershelpline");  
	sb.delete(2,5);
	System.out.println(sb); 
	}  
}  
Output :
Coshelpline

Example : A Java program to reverse the given string using Stringbuffer class method. [ reverse() ]

class Example
{  
     public static void main(String args[])
	{  
	StringBuffer sb=new StringBuffer("CodersHelpline");  
	sb.reverse();
	System.out.println(sb); 
	}  
}  
Output :
enilpleHsredoC

Example : A Java program to check the buffer size of the given string using Stringbuffer class method. [ capacity() ]

class Example
{  
public static void main(String args[])
	{  
	StringBuffer sb=new StringBuffer();  
	System.out.println(sb.capacity());      //Default Buffer Size = 16 
	
	sb.append("Codershelpline");	
	System.out.println(sb.capacity());     //Current Buffer Size = 16
	
	sb.append("Codershelpline is a simple site for students");  
	System.out.println(sb.capacity());     //Current Buffer Size = 58
	
	sb.append("Codershelpline is a simple site for students.It is best for tutorial as 
           well as project developing and programming languages");  
	System.out.println(sb.capacity());    //Current Buffer Size = 182	
	}  
}  
Output :
16
16
58
182

NB:
This function increases the default buffer capacity(16) of the buffer to store the more string from its current default capacity, it increases the capacity by (oldcapacity*2)+2. For example if our current capacity is 16, it will be (16*2)+2=34.

Example : A Java program to find the length of string using Stringbuilder class method. [ length() ]

class Example
{  
     public static void main(String args[])
	{  
	int len;
	StringBuilder sb=new StringBuilder("Codershelpline");  
	len=sb.length();
	System.out.println(len); 
	}  
}  
Output :
14

NB : StringBuilder class conatains almost similar functions, in syntax and definition, of StringBuffer class except classname.