How to convert an int array to String with toString method in Java

What you want is the Arrays.toString(int[]) method:

import java.util.Arrays;

int[] array = new int[lnr.getLineNumber() + 1];
int i = 0;

..      

System.out.println(Arrays.toString(array));

There is a static Arrays.toString helper method for every different primitive java type; the one for int[] says this:

public static String toString(int[] a)

Returns a string representation of the contents of the specified array. The string representation consists of a list of the array's elements, enclosed in square brackets ("[]"). Adjacent elements are separated by the characters ", " (a comma followed by a space). Elements are converted to strings as by String.valueOf(int). Returns "null" if a is null.