[DERBY-1573] Unsafe synchronization in NetworkServerControlImpl

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 10.2.1.6
• Fix Version/s: 10.4.1.3
• Component/s: Network Server
• Assignee: Thomas Nielsen
• Reporter: Knut Anders Hatlen
• Created: 22/Jul/06 20:52
• Updated: 29/Jun/09 13:13
• Resolved: 21/Jun/07 07:16

Description

NetworkServerControlImpl has some constructs like this one:

if (logWriter != null)
{
synchronized(logWriter)

{ logWriter.println(msg); }

}

Since logWriter might be set to null after the test for logWriter!=null and before synchronized(logWriter), one might get a NullPointerException. It would be safer to write this instead:

PrintWriter lw = logWriter;
if (lw != null) {
synchronized (lw)

{ lw.println(msg); }

}