ResultSet instance is not null, but next() call throws NullPointerException

Question

I have two cursors which are used to display details in UI.

headerCur = (ResultSet) cstmt.getObject(4);
serialCur = (ResultSet) cstmt.getObject(5);

When the user enters a wrong value, it goes to serialCur.next().

while (serialCur.next()) {
    // ...
}

However, it throws a NullPointerException.

I have logged and found that the serialCur is not null, but the next() call throws null pointer exception anyway.

How is this caused and how can I solve it?

can you provide the full stacktrace in your question. and the coding as well — msagala25, Dec 01 '16 at 12:08
@MaxG there is no `hasNext()` on a `ResultSet` - [`next()`](https://docs.oracle.com/javase/8/docs/api/java/sql/ResultSet.html#next--) is the right one to be using here — JonK, Dec 01 '16 at 12:09
@JonK you're right... it means that the result set throws exception. so try catch block? — MaxG, Dec 01 '16 at 12:14
try go to loop if ResultSet has a value .use if `(resultSet.isBeforeFirst() ) { ` — Nipun Alahakoon, Dec 01 '16 at 12:17

score -2 · Answer 1 · answered Dec 01 '16 at 12:21

-2

Use

 while (serialCur.isBeforeFirst() ) {
// ...
}

OR

if(serialCur.isBeforeFirst()) {
while (serialCur.next() ) {
// ...
} 
}

to check if result set has a value

answered Dec 01 '16 at 12:21

Nipun Alahakoon

1 Answers1