Question

/*
   * Returns a new array of students containing only those students from the given roster that belong
   * to the given academic program
   * The resulting array must not contain any null entries
   * Returns empty array (length == 0) if no students belong to the program
   */
   public static UStudent[] filterByProgram(String program, UStudent[] roster) {
       //YOUR CODEf
       int counter=0;
       for(int i=0;i<roster.length;i++) {
           if(roster[i].getAcademicProgram().equals(program)) {
               counter++;
               UStudent[] Studentbelongprogram = new UStudent[counter];
               Studentbelongprogram[i]=roster[i];
               roster=Studentbelongprogram;
           }else {
               return new UStudent[0];
           }

       }
       return roster;  
   }

Answer 1

Use the following code snippet to achieve the goal:

I have used Java Stream API to achieve this. Filtered out any null values and next filter will shortlist the matching elements.

public static UStudent[] filterByProgram(String program, UStudent[] roster) {
  

    UStudent[] result = Arrays.stream(roster)

        .filter(x -> x!=null)

        .filter(x -> x.getAcademicProgram().equals(program))

        .collect(Collectors.toList()).stream().toArray(UStudent[]::new);

return result;  

   }

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Do not forget to add imports

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import java.util.*;

import java.util.stream.Collectors;

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