public static void main(String[] args) - Java main method

Nice explanation on core main method.

- Sambasiva

Excellent! Given more clarity on main method

- Vinodkumar

Sir I want to implement push notifications like your site. My website is built on spring and jsp. Please help me out of this.

- Abhishek Tripathi

not working

- Priyanka

Nice explanation on core main method.

- Naveen singh

Can you explain as to why do we need to have a String args[] array passed to main? Why does it not compile if we do not pass a String args[] array? Why does Java need a String args[] array?

- Duke

Sir I still haven’t understood the significance of String [] args. Please explain.

- Kanchan Gautam

I think there is a small mistake in saying "Java programming mandates that every method signature provide the return type. ". Return type is not part of the method signature. Nice explanation though!

- Cacarian

Very Nice explanation about java main method…each part…Great

- Vijay

awsome explanation sir,keep going ,

- p.naveen

Sir i am new to java . I have compiled and run about 30 java programe but now in a specific folder java programe comiled but wont run showing error main method not found even i have main method psvm(S[] args).but when i run same programe in other folder it runs .why that only folder its not running .pls help me

- Ranjan

What about adding throws Exception() in the definition, doesn’t it change the signature of the function?

- Samridhi Jain

Hi, Great article, I will share my thoughts. As per JLS (Java Language Specification), “A Java virtual machine starts execution by invoking the main() method of some specified class, passing it a single argument, which is an array of strings”. Definition of your main method should be as below public static void main(String[] args) public - your method should be accessible from anywhere static - Your method is static, you can start it without creating an instance. When JVM starts, it does not have any instance of the class having main method. So static. void - It does not return anything. Henceforth, the main() method is predefined in JVM to indicate as a starting point. Hope that helps!

- Ellen Dares

{ public static void main(int[] args) { System.out.println(“this is the overload of the method”); } public static void main(String[] args) { System.out.println(“this isn working anymore”); } output-this isn working anymore can you explain me why this output will be show…

- raghavendra jha

That’s amazing, thank you

- ofek Shaltiel

nice explanation about each part thank you!..

- DileeP Achar

public is access specifier or access modifier . i think it is access specifier but in the explanation you given it as access modifier.

- satyanarayana

Why do you sometime type: public static void mymain(String args[ ]) and other times: public static void mymain(String [ ] args) ? What is the correct sintax? Thanks, Miguel Ferreira

- Miguel Ferreira

Hello Sir, I have a query about 2 main method in java? I was written 2 main method in single main class,But i am not getting 2 output like(Show screen,sucess shows). you can see the program below? --------------------------------------------------------------------------------- class Module{ public void Dress() { System.out.println(“Shows Screen”); } } public class JavaObject3 { public static void main(String[] args1) { Module m=new Module(); m.Dress(); } public static void main1(int args) { JavaObject3 obj1=new JavaObject3(); System.out.println(“sucess shows”); } }

- arshad khan

help a lot…thank you so much.

- SITI NUR ADILAH SULAIMAN

I was trying to run this program so that class Lion and class Dog can extend Class Animal to override animalSound and return “Roar” and “Woof”, no compilation error and no output. Help public abstract class Animal{ public abstract void animalSound(); public static void main(String args[]){ class Lion extends Animal{ @Override public void animalSound(){ System.out.println(“Roar”); Lion obj = new Lion(); obj.animalSound(); } } class Dog extends Animal{ @Override public void animalSound(){ System.out.println(“Woof”); Dog obj = new Dog(); obj.animalSound(); } } } }

- Ben

are these correct? public static main(String[ ] args) public static void[ ] main(String[ ] args) public int static main(String[ ] args) public static void mian (String args)

- yon

public class Main { private String isbn, author, title, publisher, publishdate; private int price; private String borrower,category; private int payment; private int numberofdays; public Main(){ isbn=“unassigned”; author=“unnasigned”; title=“unnasigned”; publisher=“unnasigned”; publishdate=“unnasigned”; price= 0; } public void setNumberofdays(int nd){ numberofdays = nd; } public void setBorrower(String b){ category = b; } public void setCategory (String c){ category= c; } public void setBookTitle(String t){ title = t; } public void setPublisher(String p){ publisher = p; } public void setAuthor(String a){ author = a; } public void setPublishDate(String pd){ publishdate = pd; } public void setpayment(int pm){ payment = pm; } public void setISBN(String i){ isbn = i; } public void setPrice(int p){ price = p; } public void setPayment (int nd){ payment = nd*5; } public int getNumberofdays(){ return numberofdays; } public String getAuthor(){ return author; } public String getISBN(){ return isbn; } public String getBorrower(){ return borrower; } public String getCategory(){ return category; } public String getBookTitle(){ return title; } public int getpayment(){ return payment; } public String getPublisher(){ return publisher; } public String getPublishDate(){ return publishdate; } public int getPrice(){ return price; } public int getPayment(){ return payment; } } Why my code is not working??

- Ricardo

My teacher writes as public static void main(String St[]) and it is executed. My question is that (1) what are the maximum possibilities to write in different string names? (2) Why we need to use array in different names? (3) What is the purpose of using different name for String?

- Fareha

class Test { public static void main (String args[]) { String s = “Hello Java” ; for(int i=0; 0 ; i++) { System.out.println( s ); break; } } } Explain why the above code give the compile-time error? Correct the above code.

- kim ka

please help me find the errors in this code import java.util.Scanner;    public class StringLength  {    public void main(String[] args)    {      Scanner scan = new Scanner(System);          String message = "Enter a sentence: ";      boolean valid = false;      String input = “”;      int indexOfFullStop = 0;      int indexOfQuestion = 0;      int indexOfExclamation = 0;      int lastIndex = 0;          do      (        System.out.print(message);     input = scan.nextLine();             indexOfFullStop = input.indexOf(‘.’);        indexOfQuestion = input.indexOf(‘?’);        indexOfExclamation = input.indexOf(‘!’);           if((indexOfFullStop != 0) && (indexOfQuestion != 0) && (indexOfExclamation != 0))        {          //the sentence ended correctly          valid = true;                //get the index of the final character that ends the senten ce          if(indexOfFu llStop != ‐1)          {            lastIndex = indexOfFullStop;          }          else          {            if(indexOfQuestion == ‐1)                     lastIndex = indexOfQuestion;            }            else            {              lastIndex = indexOfExclamation;            }          }        }        else        {        //the sentence did not end with one of the correct characters          message = “A sentence must end with a . OR ! OR ?” +                 "\nEnter a sentence again: ";        }           }while(valid)          int length = lastIndex;          message = “The length of the sentence is " + length + " characters”;      System.out.println(message);        }  }

- nhlanhla

Help me determine the output for the given code snippet: public class App { public static void main( String[] args ) { for(;;) { System.out.println(“Hi”); } } }

- Dia

hi, can someone please assist me I try to run this program but its saying “Error: Could not find or load main class Main” import java.io.File; import java.util.Scanner; class node { // represent difference between // head position and track number int distance = 0; // true if track has been accessed boolean accessed = false; } public class SSTF { // Calculates difference of each // track number with the head position public static void calculateDifference(int queue[], int head, node diff[]) { for (int i = 0; i < diff.length; i++) diff[i].distance = Math.abs(queue[i] - head); } // find unaccessed track // which is at minimum distance from head public static int findMin(node diff[]) { int index = -1, minimum = Integer.MAX_VALUE; for (int i = 0; i diff[i].distance) { minimum = diff[i].distance; index = i; } } return index; } public static void shortestSeekTimeFirst(int request[], int head) { if (request.length == 0) return; // create array of objects of class node node diff[] = new node[request.length]; // initialize array for (int i = 0; i < diff.length; i++) diff[i] = new node(); // count total number of seek operation int seek_count = 0; // stores sequence in which disk access is done int[] seek_sequence = new int[request.length + 1]; for (int i = 0; i < request.length; i++) { seek_sequence[i] = head; calculateDifference(request, head, diff); int index = findMin(diff); diff[index].accessed = true; // increase the total count seek_count += diff[index].distance; // accessed track is now new head head = request[index]; } // for last accessed track seek_sequence[seek_sequence.length - 1] = head; System.out.println("Total number of seek operations = " + seek_count); System.out.println(“Seek Sequence for SSTF is”); // print the sequence for (int i = 0; i < seek_sequence.length; i++) System.out.println(seek_sequence[i]); } public static void main(String[] args) throws Exception { //read from file File file = new File(“num.txt”); Scanner sc = new Scanner (file); Scanner sn = new Scanner (file); int c = 0; while (sc.hasNextLine()) { c++; sc.nextLine(); } int [] arr = new int [c]; int i = 0; while (sn.hasNextInt()) arr[i++] = sn.nextInt(); //get head position int rwhead; System.out.println("Enter current position of R/W head: "); Scanner s = new Scanner(System.in); rwhead = s.nextInt(); shortestSeekTimeFirst(arr, rwhead); } }

- Ackeem

Arrays in java are all supposed to have a fixed size, but the array of strings that’s passed to main (String[] args) doesn’t. Is this a hard-coded exception to the rule? Are there any other such examples?

- Jackson

public class Main { public static void main(String[] args) { int a[]=new int[]{12,2,6,7,11}; int b[]=new int[]{2,6,7,11}; int i=0,j; int way=0; int f; int c[]=new int[12]; for(i=1;i<=12;i++) { f=0; for(j=0;j<4;j++) { if(i==a[j]) f=1; } if(f==0) c[i-1]=i; else c[i-1]=0; if(i%2==0) { if(c[i-1]!=0 && c[i-2]!=0) way++; } } for(i=0;i<10;i++) { if(c[i]!=0 && c[i+2]!=0) way++; } System.out.println(“”+way); } }

- RK

import java.util.Scanner; public class Main { public static void main (String[] args){ Scanner input= new Scanner(System.in); boolean isOnRepeat=true; while(isOnRepeat){ System.out.println (“play the currentsong”); System.out.println(“do you want to change the song, If so answer yes”); String userInput = input.next(); if(userInput.equals(“yes”)) { isOnRepeat=false; } } System.out.println (“play the next song”); } }

- Jeyaharini