Show java.util.logging.Logger logs in Android Studio logcat

Question

I need to watch the log from socket.io-client-java in Android Studio logcat. For example: https://github.com/socketio/socket.io-client-java/blob/master/src/main/java/io/socket/client/IO.java#L70

1. Why don't I see the output of logger.fine(String.format("ignoring socket cache for %s", source)); in the logcat?

2. The logger in the above example is set to Fine, but in Android Studio logcat there is no Fine level (only Verbose, Debug, Info, Warn, Error, Assert). How to translate the level from java.util.logging.Logger to Android Studio logcat?

Answer 1

OK, Logcat doesn't show it because default logger level is info.

Here is solution that works for me very well. I debug socket.io now in main activity

                import io.socket.client.Manager;
                import io.socket.client.Socket;
                @Override
                    protected void onCreate(Bundle savedInstanceState) {
                        super.onCreate(savedInstanceState);
                        AndroidLoggingHandler.reset(new AndroidLoggingHandler());           
                        java.util.logging.Logger.getLogger(Socket.class.getName()).setLevel(Level.FINEST);
                        java.util.logging.Logger.getLogger(io.socket.engineio.client.Socket.class.getName()).setLevel(Level.FINEST); 
                        java.util.logging.Logger.getLogger(Manager.class.getName()).setLevel(Level.FINEST);
                        }

Possible util class

import android.util.Log;
import java.util.logging.*;
public class AndroidLoggingHandler extends Handler {

    public static void reset(Handler rootHandler) {
        Logger rootLogger = LogManager.getLogManager().getLogger("");
        Handler[] handlers = rootLogger.getHandlers();
        for (Handler handler : handlers) {
            rootLogger.removeHandler(handler);
        }
        LogManager.getLogManager().getLogger("").addHandler(rootHandler);
    }

    @Override
    public void close() {
    }

    @Override
    public void flush() {
    }

    @Override
    public void publish(LogRecord record) {
        if (!super.isLoggable(record))
            return;

        String name = record.getLoggerName();
        int maxLength = 30;
        String tag = name.length() > maxLength ? name.substring(name.length() - maxLength) : name;

        try {
            int level = getAndroidLevel(record.getLevel());
            Log.println(level, tag, record.getMessage());
            if (record.getThrown() != null) {
                Log.println(level, tag, Log.getStackTraceString(record.getThrown()));
            }
        } catch (RuntimeException e) {
            Log.e("AndroidLoggingHandler", "Error logging message.", e);
        }
    }

    static int getAndroidLevel(Level level) {
        int value = level.intValue();
        if (value >= 1000) {
            return Log.ERROR;
        } else if (value >= 900) {
            return Log.WARN;
        } else if (value >= 800) {
            return Log.INFO; 
        } else {
            return Log.DEBUG;
        }
    }
}

here is original answer: https://stackoverflow.com/a/9047282/5127756