How to convert String to long in Java

There are three ways to convert a String to long value.

1) Long.parseLong: All the characters in the String must be decimal numbers except the first character which can have minus ‘-‘. For e.g. long var = Long.parseInt("-123"); is allowed and the resultant value of var would be -123.
2) Long.valueOf: Returns a Long object holding the value of the specified String. Like parseLong it also allows minus ‘-‘ in place of first char in the String.
3) Long(String s) constructor : Long class has a constructor which allows String argument and constructs a newly allocated Long object that represents the long value indicated by the String parameter. The string is converted to a long value in exactly the manner used by the parseLong method for radix 10.

Example

public class Example {
   public static void main(String[] args)
   {
       String str="203456";
       //Conversion using parseInt method
       long num = Long.parseLong(str);

       //Conversion using valueOf method
       long num2 = Long.valueOf(str);

       //Conversion: Long(String s) constructor
       long num3 = new Long(str);

       //Displaying variables values
       System.out.println(num);
       System.out.println(num2);
       System.out.println(num3);		
   }
}

Output:

203456
203456
203456