Handle core date API changes.

logging/src/com/dmdirc/addons/logging/LoggingManager.java

 import java.nio.file.Paths;
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
+import java.time.format.DateTimeFormatter;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
     @Handler
     public void handleChannelGotTopic(final ChannelGotTopicEvent event) {
         final String filename = locator.getLogFile(event.getChannel());
-        final DateFormat timeFormat = new SimpleDateFormat("HH:mm:ss");
-        final DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy");
-
         appendLine(filename, "*** Topic is: %s", event.getTopic().getTopic());
         appendLine(filename, "*** Set at: %s on %s by %s",
-                timeFormat.format(event.getTopic().getDate()),
-                dateFormat.format(event.getTopic().getDate()),
+                event.getTopic().getDate().format(DateTimeFormatter.ofPattern("HH:mm:ss")),
+                event.getTopic().getDate().format(DateTimeFormatter.ofPattern("dd/MM/yyyy")),
                         event.getTopic().getClient()
                                 .map(GroupChatUser::getNickname).orElse("Unknown"));
     }

ui_swing/src/com/dmdirc/addons/ui_swing/dialogs/errors/ErrorsDialogController.java

 import com.dmdirc.logger.ErrorReportStatus;
 import com.dmdirc.ui.core.errors.DisplayableError;
 
-import java.text.SimpleDateFormat;
+import java.time.format.DateTimeFormatter;
 import java.util.Optional;
 
 import javax.swing.JButton;
                 table.getSelectionModel().setSelectionInterval(-1, -1);
             }
             date.setText(selectedError.map(DisplayableError::getDate)
-                    .map(d -> new SimpleDateFormat("MMM dd hh:mm aa").format(d)).orElse(""));
+                    .map(d -> d.format(DateTimeFormatter.ofPattern("MMM dd hh:mm aa"))).orElse(""));
             severity.setText(selectedError.map(DisplayableError::getSeverity)
                     .map(ErrorLevel::name).orElse(""));
             reportStatus.setText(