Null pointer exception

I'm practicing on Module 20 testng framework.

This code is not working in my Eclipse

System.out.println(System.getProperty("user.dir"));
xls_Reader x= new Xls_Reader(System.getProperty("user.dir"+"\\src\\com\\xls\\Suite.xlsx");


but if i gave Full path of Application like "E:\\Mrudula\\TOOLSQAEXAMPLE\\Core_Framework\\src\\com\\xls\\Suite.xlsx");
then its working fine.Not giving exception



[code:csj3ns9q]
package test;
import com.util.Xls_Reader;
public class SuiteRunmode {
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println(System.getProperty("user.dir"));
Xls_Reader x= new Xls_Reader(System.getProperty("user.dir"+"\\src\\com\\xls\\Suite.xlsx"));
isSuiteRunnable(x,"A Suite");

}

public static boolean isSuiteRunnable(Xls_Reader xls, String suiteName){
for(int i=2; i<=xls.getRowCount("TestSuite"); i++){
System.out.println(xls.getCellData("TestSuite", "TSID", i));
System.out.println(xls.getCellData("TestSuite", "Runmode", i));
}

return false;

}

}

[/code:csj3ns9q]

while running code giving [b:csj3ns9q] NullpointerException[/b:csj3ns9q]


java.lang.NullPointerException
at java.io.FileInputStream.<init>(Unknown Source)
at java.io.FileInputStream.<init>(Unknown Source)
at com.util.Xls_Reader.<init>(Xls_Reader.java:33)
at test.SuiteRunmode.main(SuiteRunmode.java:10)
Exception in thread "main" java.lang.NullPointerException
at com.util.Xls_Reader.getRowCount(Xls_Reader.java:45)
at test.SuiteRunmode.isSuiteRunnable(SuiteRunmode.java:17)
at test.SuiteRunmode.main(SuiteRunmode.java:11)