Q:

Scanning and getting runtime error

I'm trying to write the solution to this question: http://sharecode.io/section/problemset/problem/1088 but I'm getting a runtime error
and Eclipse kepler and ideone.com compiling are different for me. I dont understand why.
And actually i want to ask why this code System.out.println("String #"+(i+1)); runs first in the for loop and `str = br.readLine();? doesnt work correctly in order?
import java.io.IOException;
public class Main {
public static void main(String args[]) throws IOException {
    java.io.InputStreamReader isr = new java.io.InputStreamReader(System.in);
    java.io.BufferedReader br = new java.io.BufferedReader(isr, 16 * 1024);

    int testcase = br.read();
    String str = "";
    String[] strarray=null;

    for(int i=0;i<testcase;i++){
        str = br.readLine();
        strarray = str.split("");
        for (int j = 1; j < strarray.length; j++) {
            if (strarray[j].equals("A"))
                strarray[j] = "B";
            else if (strarray[j].equals("B"))
                strarray[j] = "C";
            else if (strarray[j].equals("C"))
                strarray[j] = "D";
            else if (strarray[j].equals("D"))
                strarray[j] = "E";
            else if (strarray[j].equals("E"))
                strarray[j] = "F";
            else if (strarray[j].equals("F"))
                strarray[j] = "G";
            else if (strarray[j].equals("G"))
                strarray[j] = "H";
            else if (strarray[j].equals("H"))
                strarray[j] = "I";
            else if (strarray[j].equals("I"))
                strarray[j] = "J";
            else if (strarray[j].equals("J"))
                strarray[j] = "K";
            else if (strarray[j].equals("K"))
                strarray[j] = "L";
            else if (strarray[j].equals("L"))
                strarray[j] = "M";
            else if (strarray[j].equals("M"))
                strarray[j] = "N";
            else if (strarray[j].equals("N"))
                strarray[j] = "O";
            else if (strarray[j].equals("O"))
                strarray[j] = "P";
            else if (strarray[j].equals("P"))
                strarray[j] = "Q";
            else if (strarray[j].equals("Q"))
                strarray[j] = "R";
            else if (strarray[j].equals("R"))
                strarray[j] = "S";
            else if (strarray[j].equals("S"))
                strarray[j] = "T";
            else if (strarray[j].equals("T"))
                strarray[j] = "U";
            else if (strarray[j].equals("U"))
                strarray[j] = "V";
            else if (strarray[j].equals("V"))
                strarray[j] = "W";
            else if (strarray[j].equals("W"))
                strarray[j] = "X";
            else if (strarray[j].equals("X"))
                strarray[j] = "Y";
            else if (strarray[j].equals("Y"))
                strarray[j] = "Z";
            else if (strarray[j].equals("Z"))
                strarray[j] = "A";

        }
         System.out.println("String #"+(i+1));
         for(int k =0 ; k<strarray.length;k++)
         System.out.print(strarray[k]);
    }
}
}

A:

With
int testcase = br.read();

you read the first character from the input. And if your whole input is only one character,
the entire line is already read, so that 
str = br.readLine();

has nothing to to and the first output you see is: String #1
You can change reading the testcase number to:
int testcase = Integer.valueOf(br.readLine());

But you should handle NumberFormatException

