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Q) Develop and run a java application that displays hello world on the screen?


A)

Step 1)
Create a folder with any name
Ex : “hello”
In this case “hello” folder acts as default package

Step 2)
Source code development

/*hello.java*/

Class hello
{
       Public static void main(String args[])
           {
                System.out.println(“hello world”);
           }
}



Step 3)
Program compile
Javac hello.java
-> ” javac” command is given to the os. os invokes “java compiler process” To the java compiler process , “hello.java” is given as input.
-> If no syntactical errors are found, then java compiler creates a class file “hello.class” In java, classes are compiled to “.class” files. But not the files.


Step 4)
Program execution
Java hello

-> “java” command is given to os. Os invokes the java virtual machine (JVM). JVM loads “hello.class” file from secondary memory (Hard Disk) into primary memory (RAM) JVM calls main () method.

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