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StringBuilder class in Java

StringBuilder is identical to StringBuffer except for one important difference that it is not synchronized, which means it is not thread safe. Its because StringBuilder methods are not synchronised.

StringBuilder Constructors

  1. StringBuilder ( ), creates an empty StringBuilder and reserves room for 16 characters.
  2. StringBuilder ( int size ), create an empty string and takes an integer argument to set capacity of the buffer.
  3. StringBuilder ( String str ), create a StringBuilder object and initialize it with string str.

Difference between StringBuffer and StringBuilder class

StringBuffer classStringBuilder class
StringBuffer is synchronized.StringBuilder is not synchronized.
Because of synchronisation, StringBuffer operation is slower than StringBuilder.StringBuilder operates faster.

Example of StringBuilder

class Test {
 public static void main(String args[])
  StringBuilder str = new StringBuilder("study");
  str.append( "tonight" );
  str.replace( 6, 13, "today");
  str.replace( 6, 13, "today");

studytonight studyttoday yadottyduts