String
String is stored in the Constant String Pool.
Every immutable object in Java is thread safe ,that implies String is also thread safe . String
can not be used by two threads simultaneously.
String once assigned can not be changed.
StringBuffer
StringBuffer is mutable means one can change the value of the object . The object created
through StringBuffer is stored in the heap. StringBuffer has the same methods as the
StringBuilder , but each method in StringBuffer is synchronized that is StringBuffer is thread
safe .
Due to this it does not allow two threads to simultaneously access the same method . Each
method can be accessed by one thread at a time .
But being thread safe has disadvantages too as the performance of the StringBuffer hits due
to thread safe property . Thus StringBuilder is faster than the StringBuffer when calling the
same methods of each class.
String Buffer can be converted to the string by using toString() method.
StringBuffer demo1 = new StringBuffer("Hello") ;
// The above object stored in heap and its value can be changed .
demo1=new StringBuffer("Bye");
// Above statement is right as it modifies the value which is allowed in the StringBuffer
StringBuilder
StringBuilder is same as the StringBuffer , that is it stores the object in heap and it can also
be modified . The main difference between the StringBuffer and StringBuilder is
that StringBuilder is also not thread safe.StringBuilder is fast as it is not thread safe .
StringBuilder demo2= new StringBuilder("Hello");
// The above object too is stored in the heap and its value can be modified
demo2=new StringBuilder("Bye");