can't understand - NoClassDefFoundError

[Satyendra Hari]

last week i has a project on railway reservation. Its code goes here:

import  java.io.*;
    
    public class JMain{
    public static void main(){
    try{
    reservation r=new reservation();
    r.doMenu();
    }catch(Exception e){System.out.println(e);}
    }
    }
    
  
    class reservation
    {
    InputStreamReader isr=new InputStreamReader (System.in);
    BufferedReader br=new BufferedReader (isr);
    //System.out.print("Please enter a word");
    int pno[]=new int[275];
    String name[]=new String[275];
    String phno[]=new String[275];
    int age[]=new int[275];
    int cl[]=new int[275];
    int pcount=0;
    int pnum=1;
    int max1=75;
    int max2=125;
    int max3=175;
    public void doMenu() throws Exception
    {
    int cho=0;
    do
    {
    System.out.println("\f");    
    System.out.println("1.Book ticket");
    System.out.println("2.Cancel ticket");   
    System.out.println("3.Exit");
    System.out.println("Please enter your choice");
    cho=Integer.parseInt(br.readLine());
    switch(cho)
    {
    case 1 :DoBook();
    break;
    case 2 :DoCancel();
    break;
    case 3 :DoExit();
    break;    
    default :System.out.println("Invalid choice");
    }
    char e=(char)br.read();
    }while(cho!=6);
    }
    
    private void doBook()throws Exception
    {
    System.out.println("Please enter the class of ticket");
    System.out.println("1. AC\t 2. First\t 3. Sleeper\t");
    int c=Integer.parseInt(br.readLine());
    System.out.println("Please enter no. of tickets");
    int t=Integer.parseInt(br.readLine());
    int ticketAvailable=0;
    if(c==1 && max1>=t)
    {
    ticketAvailable=1;
    }
    if(c==2 && max2>=t)
    {
    ticketAvailable=1;
    }
    if(c==3 && max3>=t)
    {
    ticketAvailable=1;
    }
    if(ticketAvailable==1)
    {
    for(int i=0;i<t;i++)
    {
    pno[pcount]=pnum;
    System.out.println("Please enter your name");
    name[pcount]=br.readLine();
    System.out.println("Please enter your age");
    age[pcount]=Integer.parseInt(br.readLine());
    cl[pcount]=c;
    System.out.println("Please enter your phno");
    phno[pcount]=br.readLine();
    pcount++;
    pnum++;
    System.out.println("Ticket successfully booked");
    }//for
    if(c==1)
    {
    max1-=t;
    System.out.println("Please pay Rs."+t*1500);
    }
    if(c==2)
    {
    max2-=t;
    System.out.println("Please pay Rs."+t*1200);
    }
    if(c==3)
    {
    max3-=t;
    System.out.println("Please pay Rs."+t*1000);
    }
    }
    }
    private void doCancel()throws Exception
    {
    int t_pno[]=new int[275];
    String t_name[]=new String[275];
    String t_phno[]=new String[275];
    int t_age[]=new int[275];
    int t_cl[]=new int[275];
    int t_pcount=0;
    int passengerFound=0;
    System.out.println("Please enter your passenger no.");
    int p=Integer.parseInt(br.readLine());
    for(int i=0;i<pcount;i++)
    {
    if(pno[i]!=p)
    {//transfer
    t_pno[t_pcount]=pno[i];
    t_name[t_pcount]=name[i];
    t_phno[t_pcount]=phno[i];
    t_age[t_pcount]=age[i];
    t_cl[t_pcount]=cl[i];
    t_pcount++;
    }
    else
    {
    passengerFound=1;
    if(cl[i]==1)
    {
    max1++;
    System.out.println("Please collect refund of Rs."+1800);
    }
    if(cl[i]==2)
    {
    max2++;
    System.out.println("Please collect refund of Rs."+1500);
    }
    if(cl[i]==3)
    {
    max3++;
    System.out.println("Please collect refund of Rs."+1000);
    }//else
    }//if
    }
    if(passengerFound==1)
    {
    pno=t_pno;
    name=t_name;
    age=t_age;
    cl=t_cl;
    phno=t_phno;
    pcount=t_pcount;
    System.out.println("ticket successfully cancelled");
    }
    }//method
        private void doExit()
    {
    System.out.println("Exit");    
    }
    }  
  

Above program is compiling sucessfully
But on running the program in console i get a "Exception in thread "main" java.lang.NoClassDefFounfError: JMain Error,which I failed to sort out.
Please help me sorting this error..
Thank you

[edit]Disable Smilies. CR[/edit]
[ November 10, 2008: Message edited by: Campbell Ritchie ]

[Ernest Friedman-Hill]

Hi,

Welcome to JavaRanch!

You've probably got a setting for the CLASSPATH environment variable which does not include '.' (dot, the current directory.) As a result, java can't find JMain.class, even though it exists.

Try

java -cp . JMain

(that's java space dash cp space dot space JMain).