String class in Java

String class in java 

- case sensitive (lower case gives an error)

- no need 'new' keyword 

- It restricts the creation of a string instance consisting of the same string.

- It does not allow changes to the data in the String instance.

If you want to make variables that hold the strings, you need to create object first.

class Student
{
    public static void main(String[] args)
    {
        String hello = new String("Hello Java") // use 'new' keyword to create new object
    }
}

Luckily we do not need 'new' keyword when we use String class. Java made it easier because we use it a lot

class Student
{
    public static void main(String[] args)
    {
        String hello = String("Hello Java");
        System.out.println(hello);    
    }
}

no need to initialize it immediately. We can use it like primitive data types.

class Student
{
    public static void main(String[] args)
    {
        String hello;
        hello = "Hello Java ";
 
        System.out.println(hello);    
    }
}

String initialization

what is the difference between 'String hello = "";' and 'String hello = null' ?;

String hello = ""; // preferred way to initialize.  It has zero characters and it is doing an operation on it, 

String hello = null; // no references to it, therefore, it will give you NPE(NullPointerException) 

Reference

https://www.edureka.co/blog/java-string/

https://www.w3resource.com/java-tutorial/exploring-methods-of-string-class.php

https://www.geeksforgeeks.org/different-ways-for-integer-to-string-conversions-in-java/