getting java.lang.NoSuchMethodError: main error! thanks =)

import java.util.Scanner; import java.util.ArrayList; public class SchoolApp { String School = "Bogus School"; { int input1 = 0; int count = 0; // private ArrayList modules = null; //private ArrayList moduleList = null; //private ArrayList studentList = null; Scanner scan = new Scanner (System.in); while (input1 != 9) { System.out.println("\nStudent Registration System\n1. Add a student\n"+ "2. Remove a student\n3. Add a module\n4. Remove a module\n5. Display a module list\n"+ "6. Display student list\n7. Register module(s) for a student\n8. Display module(s) "+ "taken by a student\n9. Quit"); System.out.println("\nEnter Your Choice:\n"); input1 = scan.nextInt(); } class Student{ private int studentID; private String name; private ArrayList modules = null; //this is the constructor public Student(int studentID, String name) { //some code here } } class Module { private int moduleID, population, classLimit, semester; private String moduleName; //this is the constructor public Module(int moduleID, String moduleName, int classLimit, int semester) { //some code here } //public boolean isFull() { //some code inside here //} //public boolean isOfferedInSem(int sem) { //some code inside here // } //public String toString() { //some code inside here // } } class School { private String schoolName; public ArrayList moduleList = null; public ArrayList studentList = null; public void addStudent() { String name; String StudentID; Scanner scan1 = new Scanner (System.in); System.out.println ("Please enter the student name to be added"); name = scan1.nextLine(); System.out.println ("Please enter the student ID to be added"); StudentID = scan1.nextLine(); String Student = StudentID + name; System.out.print ("Added " + StudentID + " " + name); } public void removeStudent() { String StudentID; Scanner scan2 = new Scanner (System.in); System.out.println ("Please enter the student ID to be removed"); StudentID = scan2.nextLine(); } public void addModule() { String Module; Scanner scan3 =new Scanner (System.in); System.out.println ("Please enter the module to be added"); Module = scan3.nextLine(); } public void removeModule() { String module; Scanner scan4 = new Scanner (System.in); System.out.println ("Please enter the module to be removed"); module = scan4.nextLine(); } public void displayModule () { String dModule; Scanner scan5 = new Scanner (System.in); System.out.println ("Please enter the modules to be displayed"); dModule = scan5.nextLine (); } } } } }

i keep getting java.lang.NoSuchMethodError: main
Exception in thread "main" when i try to run it but it complies fine. Can anyone advise? Thanks!

Also i would like to ask how would i save the student name and ID into an arraylist and retrieve it from the arraylist to delete? Thanks for help!

um.... you don't have a main method in the code you posted. a class is not require to have a main to compile, only to run.

winnie Lim wrote:
Also i would like to ask how would i save the student name and ID into an arraylist and retrieve it from the arraylist to delete? Thanks for help!

Id is a Key and Student name is values, that's sound good for Map collections

is there anything wrong with my School class?

i can't seem to call the addStudent, removeStudent, methods in my public class SchoolApp. i get error "cannot find symbol method addStudent();"

thanks alot for the java.lang.NoSuchMethodError! solved!

class School { private String schoolName; public ArrayList moduleList = null; public ArrayList studentList = null; public void addStudent() { String name; String StudentID; Scanner scan1 = new Scanner (System.in); System.out.println ("Please enter the student name to be added"); name = scan1.nextLine(); System.out.println ("Please enter the student ID to be added"); StudentID = scan1.nextLine(); String Student = StudentID + name; System.out.print ("Added " + StudentID + " " + name); } public void removeStudent() { String StudentID; Scanner scan2 = new Scanner (System.in); System.out.println ("Please enter the student ID to be removed"); StudentID = scan2.nextLine(); } public void addModule() { String Module; Scanner scan3 =new Scanner (System.in); System.out.println ("Please enter the module to be added"); Module = scan3.nextLine(); } public void removeModule() { String module; Scanner scan4 = new Scanner (System.in); System.out.println ("Please enter the module to be removed"); module = scan4.nextLine(); } public void displayModule () { String dModule; Scanner scan5 = new Scanner (System.in); System.out.println ("Please enter the modules to be displayed"); dModule = scan5.nextLine (); } public class SchoolApp { public static void main (String[] args){ String School = "Bogus School"; { int input1 = 0; int count = 0; // private ArrayList modules = null; //private ArrayList moduleList = null; //private ArrayList studentList = null; Scanner scan = new Scanner (System.in); while (input1 != 9) { System.out.println("\nStudent Registration System\n1. Add a student\n"+ "2. Remove a student\n3. Add a module\n4. Remove a module\n5. Display a module list\n"+ "6. Display student list\n7. Register module(s) for a student\n8. Display module(s) "+ "taken by a student\n9. Quit"); System.out.println("\nEnter Your Choice:\n"); input1 = scan.nextInt(); } switch (input1) { case 1: System.out.println("Add A Student\n"); addStudent(); break; case 2: System.out.println("\nRemove a student\n"); removeStudent(); break; case 3: System.out.println("\nAdd a module\n"); addModule(); break; case 4: System.out.println("\nRemove a module\n"); //removeModule; break; case 5: System.out.println("\nDisplay a module list\n"); //displayModule;

You appear to be calling addStudent() etc from another class, SchoolApp, and SchoolApp hasn't got an addStudent() method.

You need to create a School object in that main method, then invoke the methods on that object.

By the way: your addStudent method in the School class doesn't seem to do anything. It asks for the Student's name, but doesn't do anything with it. It that because the class is incomplete?

Campbell Ritchie wrote:You appear to be calling addStudent() etc from another class, SchoolApp, and SchoolApp hasn't got an addStudent() method.

You need to create a School object in that main method, then invoke the methods on that object.

By the way: your addStudent method in the School class doesn't seem to do anything. It asks for the Student's name, but doesn't do anything with it. It that because the class is incomplete?

yes the code is incomplete... i'm supposed to store it into a arraylist and retrieve it.

sorry to ask but can you teach me how to create a School object in the main method? I know it sounds stupid but i really am new and its a pressing assignment.

How do you create a new object of any class? You do the same with the School class.
And please don't go saying questions are urgent.

Campbell Ritchie wrote:How do you create a new object of any class? You do the same with the School class.
And please don't go saying questions are urgent.

erm... i really don't know how to create a new object of anything! i already tried looking through all the online tutorials but i really can't get what they mean or what how the object class in created. Please if you can, just help me out here.

This site discusses how to create a new object. It has some things that are out of your scope, but it should give a decent description on creating an object.

Creating Objects

hey thanks!

but after i declare eg School sch = new School ();

what do i do to invoke the methods in the object?

The longer I post on this forum, the more people will realize I'm full of links!

Link

That should describe how to invoke the methods of an object.

thanks! will read through and try to understand on my own.

you guys have been a great help thanks a million!!!

I am confident that link will supply all the information you need.

And . . . you're welcome