String Class (Core JAVA)

·         String class is used to handle the String value in the program. This class is available in “package java.lang.String”

·         String class is final class, it can be inherited to any subclass

·         We can create object of String class in 2 ways:

(1)    Using new operands

(2)    Using double quotes

NOTE: From jdk 1.5 onwards, 2 additional classes are introduced to create String object.

(1) String Builder

(2) String Buffer

Both cases are Mutable Classes means object value can be changed. Using these 2 classes we can create String object by using new operand only.

·         For these 2 classes reverse method is also available.

NOTE: String class designs Immutable Classes. Once string object is created its value cannot be changed. If the object values are getting changed then it will create new object instead of pointing existing one.

·         When the objects are created using new operands, then new object is created in the memory even though object is already existing “It allows Duplicate objects”

·         When String object is created by enclosing in double quotes, it creates new object only if the object is unique. Otherwise it reuses the existing object

·         The uniqueness of an object is identified based on the String value

·         String class is Immutable class. Once String object is created, its value cannot be changed

·         If the object values are changed, the it creates new object instead of changing existing one

·         In String class toString() is overrided to return the value of object

NOTE: From jdk 1.5 onwards, 2 additional classes are introduced to create String object

(1)    String Builder

(2)    String Buffer

Both classes are mutable classes, means that the object value can be changed. In these classes we can create String object by using new operand only

NOTE: For these 2 classes 1 additional method is also available by name reverse