Bug #104559 ResultSet.getObject(i, java.util.Date.class) throws NPE when the value is null

• Submitted: 6 Aug 2021 14:40
• Modified: 12 Oct 2021 16:56
• Reporter: ys y
• Status: Closed
• Category: Connector / J
• Severity: S3 (Non-critical)
• Version: 8.0.23+
• OS: Any
• Assigned to: Alexander Soklakov
• CPU Architecture: Any

[6 Aug 2021 14:40] ys y

Description:
when the value of ResultSet.getObject(columnIndex, java.util.Date.class) is null, it will prduce NPE.

How to repeat:
ResultSetImpl#getObject(int columnIndex, Class<T> type):

  else if (type.equals(java.util.Date.class)) {
    return (T) java.util.Date.from(getTimestamp(columnIndex).toInstant());
  }

getTimestamp(columnIndex) may produce NPE.

Suggested fix:
ResultSetImpl#getObject(int columnIndex, Class<T> type):

else if (type.equals(java.util.Date.class)) {
  Timestamp ts = getTimestamp(columnIndex);
  if(ts == null){
    return null;
  }
  return (T) java.util.Date.from(ts.toInstant());
}

[16 Aug 2021 9:15] Alexander Soklakov

Hi,

Thanks a lot!

Verified with the following test case:

    @Test
    public void testBug104559() throws Exception {
        String tableName = "testBug104559";
        createTable(tableName, "(`dt` DATE DEFAULT NULL)");
        this.stmt.executeUpdate("INSERT INTO " + tableName + " VALUES (null)");

        Properties props = new Properties();
        Connection con = getConnectionWithProps(props);
        Statement st = con.createStatement();
        this.rs = st.executeQuery("SELECT * FROM " + tableName);
        while (this.rs.next()) {
            System.out.println(this.rs.getObject("dt", java.util.Date.class)); // NPE !!!
        }
    }

Stack trace:

java.lang.NullPointerException
	at com.mysql.cj.jdbc.result.ResultSetImpl.getObject(ResultSetImpl.java:1346)
	at com.mysql.cj.jdbc.result.ResultSetImpl.getObject(ResultSetImpl.java:1427)
	at testsuite.simple.MetadataTest.testBug104559(MetadataTest.java:1869)

[12 Oct 2021 16:56] Daniel So

Posted by developer:
 
Added the following entry to the Connector/J 8.0.27 changelog: 

"When ResultSet.getObject(columnIndex, java.util.Date.class) was expected to return null, it caused Connector/J to throw a NullPointerException instead."