Java:prg suivant me donne aucun output

import java.io.*;
public class StuDetail 
{
  int RollNo;
}
class StudMarks extends StuDetail
{
	float sub1;
	float sub2;
	float sub3;
	float TotalMarks;
	
	void getData()
	{
		System.out.println("\nRecording Entry");
		try
		{
			BufferedReader obj=new BufferedReader(new InputStreamReader(System.in));
			String sRNo,sSub1,sSub2,sSub3;
			
			System.out.println("Enter Roll No:");
			System.out.flush();
			sRNo=obj.readLine();
			RollNo=Integer.parseInt(sRNo);
			
			System.out.println("Enter Marks for Subject 1:");
			System.out.flush();
			sSub1=obj.readLine();
			sub1=Float.parseFloat(sSub1);
			
			System.out.println("Enter Marks for Subject 2:");
			System.out.flush();
			sSub2=obj.readLine();
			sub2=Float.parseFloat(sSub2);
			
			System.out.println("Enter Marks for Subject 3:");
			System.out.flush();
			sSub3=obj.readLine();
			sub3=Float.parseFloat(sSub3);
			
			TotalMarks=sub1+sub2+sub3;
		}
		catch(Exception e)
		{}	
		}
	    void display()
	    {
	    	System.out.println("\nDisplaying Record");
	    	System.out.println("Roll No:"+RollNo);
	    	System.out.println("Subject 1:"+sub1);
	    	System.out.println("Subject 1:"+sub2);
	    	System.out.println("Subject 1:"+sub3);
	    	System.out.println("Total Marks:"+TotalMarks);
	    }
	    void TotalMarks()
	    {
	    	System.out.println("\nDisplaying Record");
	    	System.out.println("Roll No:"+RollNo);	
	    	System.out.println("Total Marks:"+TotalMarks);
	    }
	}
class StudentDatabase
{
 public static void main(String []args)
 {
	 System.out.println("\n======STUDENT DATABASE=====\n");
	 
	 float HighMark_sub1;
	 float HighMark_sub2;
	 float HighMark_sub3;
	 float StudHightMark;
	 int No_of_stud=3,choice;
	 String str;
	 char c;
	 
	 try
	 {
		BufferedReader obj=new BufferedReader(new InputStreamReader(System.in));
		System.out.print("\nEnter number of students:");
		System.out.flush();
		str=obj.readLine();
		No_of_stud=Integer.parseInt(str);
		StudMarks SMobj[]=new StudMarks[No_of_stud];
		
		while(true)
		{
			System.out.println("\nChoose your choice....");
			System.out.println("1)PASS ENTRY");
			System.out.println("2)DISPLAY ALL RECORDS");
			System.out.println("3)DISPLAT TOTAL MARKS for all students");
			System.out.println("4)DISPLAT HIGHEST MARKS in each subject");
			System.out.println("5 DISPLAY student who recived highest total marks");
			System.out.println("6 Exit");
			System.out.println("ENTER YOUR CHOICE:");
			System.out.flush();
			str=obj.readLine();
			choice=Integer.parseInt(str);
			
			switch(choice)
			{
			 case 1:
				 for(int i=0; i<No_of_stud; i++)
					 SMobj[i].getData();
				 break;
			 case 2:
				 for(int i=0; i<No_of_stud; i++)
					 SMobj[i].display();
				 break;
			 case 3:
				 for(int i=0; i<No_of_stud; i++)
					 SMobj[i].TotalMarks();
				 break;
			 case 4:break;
			 case 5:break;
			 case 6:System.out.println("\nThanks for visting.....");
			 System.exit(1);	 
			}
		} 
	 }
	 catch(Exception e)
	 {}
 }
}