Re: What is wrong with my program?

SamuelXiao,
   Two SSCCEs, two code reviews, two rewrites.
I've learned a lot today. Thanks Lew. :)

import java.util.Arrays;

public class StudentFileReaderTest {

   public static void main(String[] args) {

     Integer[] students = new Integer[30];

     Integer[] file =
     {
         // Don't fill the heap unnecessarily
         Integer.valueOf(2),
         Integer.valueOf(3),
         Integer.valueOf(1),
         Integer.valueOf(2),
         Integer.valueOf(3)
     };

     int count = 0;

     if ( file.length > 0 )
     {
       for ( int ix = 0;
             // Watch your invariants
             ix < file.length && count < students.length;
             ++ix )
       {
         // Don't perform unnecessary iterations
         if( Arrays.binarySearch( students, 0, count, file [ix] ) < 0 )
         {
           students [count] = file[ix];
           // Don't be unnecessarily verbose
           Arrays.sort( students, 0, ++count );
         }
       }
     }

     for ( int ix = 0; ix < count; ++ix )
     {
       System.out.println( students [ix] );
     }

   }

}

Bo Vance started with this:

public class Scratch {

   static Integer[] students = new Integer[30];
   static int recordCount = 0;

   public static void main(String[] args) {

     Integer[] studentFile =
     {
         new Integer(2),
         new Integer(3),
         new Integer(1),
         new Integer(2),
         new Integer(3)
     };

     Arrays.fill(students, new Integer(-1));

     for (Integer studentRecord : studentFile) {
       addStudent(studentRecord);
     }

     recordCount = 0;
     Integer test = students[recordCount];
     while (test.intValue() < 0) {
       recordCount++;
       test = students[recordCount];
     }

     for (int i = recordCount; i < students.length; i++) {
       System.out.println(students[i]);
     }

   }

   static void addStudent(Integer student) {

     if(Arrays.binarySearch(students, student) < 0) {
       students[recordCount] = student;
       recordCount++;
     }
     Arrays.sort(students);
   }

}