Can anybody help me in implementing sorted array based data structure.

Hi..I've been working on this program and now exhausted. I'm asked to input students informationin data structure. first enter number of students then their information(name, id# and gpa). I've created sorted array class(with insert, fetch, delete and update method...),Listing class which creats object of each student and holds their information, & Main sorted array class which calls other two classes.
I'm getting few errors in fetch method. doent sort properly. I'm using binary search method. I also dont understand how to input student info from main sorted array class and insert it. I was getting array out of bound error.
I'm posting my both class here. plz help me...thanks

public class SortedArray{

private int size;
private int next;
private Listing[] data;
private int mid = 0;


public SortedArray(){

next = 0;
size = 100;
data = new Listing[size];

}

public SortedArray(int n){

next = 0;
size = n;
data = new Listing[size];
}

//insert operation
public int insert(Listing newNode) {

int low = 0;

String nodeName = newNode.getName();

if(next == 0) {
data[next] = newNode.deepCopy();
next = next + 1;

return next;
}
if(next == 1) {
data[next] = newNode.deepCopy();
next = next + 1;

return next;
}
else{
low = 0;
int high = next - 1;

// System.out.println("line 1");
while (high >= low) {

mid = (low + high) / 2;
// System.out.println("mid is " + mid);

if(data[mid].compareTo(nodeName) > 0)
{high = mid - 1;
//System.out.println("high is" + high);
}
else if (data[mid].compareTo(nodeName) == 0)
break;
//return mid;
else{
low = mid + 1;
//System.out.println("low is " + low);
}
}
for(int j = next; j >= mid; j--){
data[j] = data[j-1];
// System.out.println("line 5");
}
next = next + 1;
//System.out.println("next is " + next);

data[mid] = newNode.deepCopy();
//System.out.println("mid is" + mid);
return mid;
}
// return -low-1;

}


//fatch operation
public Listing fatch(String targetKey){

System.out.println("targetkey is " + targetKey);
int low = 0;
int high = next - 1;
System.out.println("next is " + next);

while (high >= low) {
mid = (low + high) / 2;
System.out.println("fatch mid is " + mid);

if (data[mid].compareTo(targetKey) > 0) {
System.out.println("comparison output is " + data[mid].compareTo(targetKey));

System.out.println("data[mid] is "+data[mid] + "\n");
high = mid - 1;
System.out.println("fatch high is " + high);}

else if (data[mid].compareTo(targetKey) == 0){

break;}

else{
low = mid + 1;
System.out.println("fatch low is " + low);}
}

return data[mid].deepCopy();
}

import java.util.Scanner;

public class MainSortedArray{

public static void main(String[] args){

Scanner input = new Scanner(System.in);

System.out.println("Enter number of students: ");
int numStu = input.nextInt();

SortedArray studentInfo = new SortedArray();

Listing temp;
for(int i = 0; i < numStu; i++){

System.out.println("Enter name of the student: ");
String stuName = input.next();
System.out.println("Enter student ID number: ");
String idNumber = input.next();
System.out.println("Enter students GPA: ");
String stuGpa = input.next();

Listing newStudent = new Listing(stuName,idNumber,stuGpa);
System.out.println(studentInfo.insert(newStudent)) ;
}
}
}