Variables can be defined and  initialized in separate lines or in the same line

They must be defined and initialized before they can be used in your application

//import java io.*;
//javac simple.java
public class Test_this
{
public static void main(String args[])//this is an netry function must have
{
int n1 ; //just defining a variable
String str; // defining/declaring a variable
str = "my name is baba "; //initializing variable str
n1 = 25 ; //initializing a n1 variable
int l4=9;// defining and initializing variable at the same time
//variables must be initialized before you can use them
String l7="Hji";
System.out.println("hello world" + l4);
System.out.println("hello world" + l7 +str + n1);

}

}//main clas ends here