Difference between command line tool compiling and IDE compiling Java

Question

im new to java, ROOKIE... i was doing arraylist example and i compiled it on IDE it worked perfectly, i did that example on CMD it gave me an error

Note: Practice.java uses unchecked or unsafe operations.

Note: Recompile with -Xlint:unchecked for details.

so i used my googling power and googled everything, i found a answer,

by the way this is the code im talking about...

     import java.util.*;
     public class Practice{
     public static void main(String[] args){
     ArrayList mylist = new ArrayList();
     mylist.add("Maisam Bokhari");
     mylist.add("Fawwad Ahmed");
     mylist.add("Ali Asim");
     mylist.add("Maheen Hanif");
     mylist.add("Rimsha Imtiaz");
     mylist.add("Mugheer Mughal");
     mylist.add("Maaz Hussain");
     mylist.add("Asad Shahzada");
     mylist.add("Junaid Khan");
     System.out.println("Name of the student: "+mylist);
    }
}

it work perfectly on IDE (netbeans) but it gave those 2 errors on cmd

many people all over the internet and stackoverflow said that define the data type when creating an ArrayList object

ArrayList< String > mylist = new ArrayList<>();

i did this and it worked perfectly on CMD too... :)

now my question is this which i cant find on the internet

what is the difference between IDE compiling and command line tools compiling?

( i remember when i used to compile my C code in turboC and when i shifted to code::blocks i had to change some code to adjust the compiler , is this same thing ? but java was platform independent )

Answer 1

One reason for the difference is that your IDE might be using a different version of java than your command line compiler. You would see this if your Netbeans IDE uses java 1.4 or older and your command line uses 1.5 or newer.