String and String Buffer classes

In this topic, you will learn about, String and String Buffer classes.

String Classes: This class allows storing a collection of letters, numbers,s, or symbols by using the dynamic concepts. String class uses java.lang package and it also offers various pre-defined functions. By-default string class is initialized with a null value and we can use different constructors for string initialization.

To create a string:

String <string object>;
<string object>=new string(argument);


  1.  string obj; Obj=new string(’’hello!’’);
  2. string str; str=new string(10);
  3.  String str; Str=newString();

Buffer string Class: String buffer class is a peer(related) class of string but it offers facility to create variable size,we can easily increase or decrease memory size . String class also offers facility to insert element at given position and delete element from given position.

To create string Buffer:


stringBuffer <object>;

<object>=new <stringBuffer(’’string’’)>;


  1. StringBuffer str;
  2. StringBuffer str;
  3. StringBuffer str;

Difference Between String and String Buffer classes:

String Buffer classes String classes
String buffer class represent same as string but create fix size string object. String class create dynamic memory but we cannot create fix size string object
A string buffer object is of flexible size or content. String class contents and size cannot change if fix size and content defined.
String buffer offers a facility to insert substring at any position. A string cannot insert any element in the middle of the string.
String buffer allows appending given string at the end. String class object size cannot increase or decrease, so, we cant append.
String buffer uses java. util package for declaration. String class uses i.o and lang for declaration.
String buffer class object provides a set of functions like append, insert, setlength,setcharacter, etc. String class provides manipulation function only like length, char At and short.

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