JAVA

Java StringBuilder

//StringBuilder in Java represents a mutable sequence of characters.

// Example(1) Create StringBuilder without Arguments

StringBuilder name = new StringBuilder();  // Create a StringBuilder object

// Example(2) Create StringBuilder with Arguments

StringBuilder name = new StringBuilder("Computer System");

// Example(3) Change from String Object to StringBuilder Object

String name = "jack"; // String Object 

StringBuilder name2 = new StringBuilder(name);  // add String Object  in StringBuilder Constructor 

System.out.println(name2); // print StringBuilder Object

System.out.println(name2.toString); // print String Object

stringbuilder java

// Overuse of String concatenation can build large numbers of String objects
// a huge drain on performance and memory, hence code below is avoided
String firstName = "Chris";
String lastName = "Wells";
String fullName = firstName + " " + lastName;

// StringBuilder
// provides dynamic string manipulation without performance overhead of String class
StringBuilder nameBuffer = new StringBuilder("John");
nameBuffer.append(" ");
nameBuffer.append("Richard");
System.out.println(nameBuffer.toString());  //must convert to Strings before can be printed

stringbuilder java

StringBuilder objects are like String objects, except that they can be modified

stringbuilder in java

Java StringBuilder class is used to create
  mutable (modifiable) string. The Java
  StringBuilder class is same as StringBuffer
  class except that it is non-synchronized.
    
StringBuilder()
    creates an empty string Builder with the initial capacity of 16.
StringBuilder(String str)
    creates a string Builder with the specified string.
StringBuilder(int length)
    creates an empty string Builder with the specified capacity as length.    

stringbuilder example in java

public static void main(String args[]){
  	
	StringBuilder sb=new StringBuilder("Hello "); //init 		
	sb.insert(1,"Java");//now original string is changed  
	System.out.println(sb);//prints HJavaello  
}  

what is stringbuilder

It is mutable char sequence and it is not
thread safe.