What is a String in java ?

A string in java is a sequence of characters treated as a unit

Strings in Java

• standard objects with built-in language support
  • String – class for immutable (read-only) strings
  • StringBuffer – class for mutable strings

• can be converted to other types like integers and booleans
• like other classes, String has constructors and methods
• unlike other classes, String has two operators, + and += (used for concatenation)
• Strings, once created, cannot be modified!!
  • However, we can carry out operations on a string and save it as another string

Basic String Operations

• Constructors
  • public String()
    • construct a new String with the value “ ”
  • public String(String value)
    • construct a new String that is a copy of the specified String object value

• Basic methods
  • Length() : return the length of string
  • charAt() : return the char at the specified position

Example

for(int i = 0; i < str.length(); i++)
counts[str.charAt(i)]++;