Need to write WARNING Level logs to different file using filehandler but console handler still show INFO and SEVERE but NO WARNING when .level=INFO - websphere-8

Question

We have a Java application on Websphere where we need SystemOut.log only print loglevel SEVERE and INFO (using existing java.util.logging default ConsoleHandler), but we need a WARNING written to separate file using the FileHandler .
Created a LevelBasedFileHandler which takes log level and file to write and i can see the log file updated as needed.
But the Warning level's are written in SystemOut.log too, Need a way to stop them from appearing
logger.addHandler(new LevelBasedFileHandler("../logs/warning.log", Level.WARNING));
logger.setFilter(new LevelBasedFilter()); - Trying to see if i can filter
logger.setUseParentHandlers(false);
using the logger.setUseParentHandlers(false) is not printing any information to SystemOut.log if i remove it i see WARNING information too. Any idea i can filter the Warning Level from this?

Answer 1

If you filter at the logger level that will suppress log records before they reach any of the handlers. What you should do is install filters on the existing handlers.
For example, create a filter which takes a boolean:
import java.util.logging.Filter;
import java.util.logging.Level;
import java.util.logging.LogRecord;
public class WarningFilter implements Filter {
private final boolean complement;
public WarningFilter(final boolean complement) {
this.complement = complement;
}
#Override
public boolean isLoggable(LogRecord r) {
return Level.WARNING.equals(r.getLevel()) != complement;
}
}
Next you should install your filter on each handler. For example:
private static final Logger logger = Logger.getLogger("some.other.logger.name");
public static void main(String[] args) throws Exception {
boolean found = false;
for (Handler h : Logger.getLogger("").getHandlers()) {
h.setFilter(new WarningFilter(h instanceof ConsoleHandler));
}
if(!found) {
Handler h = new ConsoleHandler();
h.setFilter(new WarningFilter(true));
}
Handler h = new FileHandler();
h.setFilter(new WarningFilter(false));
logger.addHandler(h);
}