The StringBuffer is always been using for the String concatenation. However this class didn’t provide a method to clear the existing content. Why there are no clear() function?

You can use the delete(int start, int end) as dirty trick :

sb.delete(0, sb.length());

1 . Example

package com.mkyong.io;
 
public class App{
 
   public static void main (String args[]) {
 
	   StringBuffer sb = new StringBuffer();
	   sb.append("Hello ");
	   sb.append("World ");
	   sb.append("StringBuffer ");
 
	   //clear the Stringbuffer content
	   sb.delete(0, sb.length());
 
	   sb.append("String deleted ");
 
	   System.out.println(sb.toString());	   
 
   }
}

2. Output

String deleted
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