The result of invoking readLine() is read without checking to see if it is null.

Bad Practice

If there are no more lines of text to read, readLine will return null and dereferencing that will generate a null pointer exception.

String a = bufReader.readLine();
int b = a.length; // Will throw an NPE if a is null.

Recommended

String a = bufReader.readLine();

if (a == null) {
    // do something....
}

Unless you are absolutely confident that this will not happen (though it is a sensible thing to do even then), check if the result is null and perform an appropriate action if it is.

References

SpotBugs - NP_DEREFERENCE_OF_READLINE_VALUE

vivekkoya / classfiles

No ignore rules found