package cpw.mods.fml.common;

/**
 * Copied from ConsoleLogFormatter for shared use on the client
 * 
 */
import java.io.PrintWriter;
import java.io.StringWriter;
import java.text.SimpleDateFormat;
import java.util.logging.Formatter;
import java.util.logging.Level;
import java.util.logging.LogRecord;

final class FMLLogFormatter extends Formatter
{
    private SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    public String format(LogRecord record)
    {
        StringBuilder msg = new StringBuilder();
        msg.append(this.dateFormat.format(Long.valueOf(record.getMillis())));
        Level lvl = record.getLevel();

        if (lvl == Level.FINEST)
        {
            msg.append(" [FINEST] ");
        }
        else if (lvl == Level.FINER)
        {
            msg.append(" [FINER] ");
        }
        else if (lvl == Level.FINE)
        {
            msg.append(" [FINE] ");
        }
        else if (lvl == Level.INFO)
        {
            msg.append(" [INFO] ");
        }
        else if (lvl == Level.WARNING)
        {
            msg.append(" [WARNING] ");
        }
        else if (lvl == Level.SEVERE)
        {
            msg.append(" [SEVERE] ");
        }
        else if (lvl == Level.SEVERE)
        {
            msg.append(" [" + lvl.getLocalizedName() + "] ");
        }

        msg.append(record.getMessage());
        msg.append('\n');
        Throwable thr = record.getThrown();

        if (thr != null)
        {
            StringWriter thrDump = new StringWriter();
            thr.printStackTrace(new PrintWriter(thrDump));
            msg.append(thrDump.toString());
        }

        return msg.toString();
    }
}

package cpw.mods.fml.common;

/**
 * Copied from ConsoleLogFormatter for shared use on the client
 * 
 */
import java.io.PrintWriter;
import java.io.StringWriter;
import java.text.SimpleDateFormat;
import java.util.logging.Formatter;
import java.util.logging.Level;
import java.util.logging.LogRecord;

final class FMLLogFormatter extends Formatter
{
    private SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    public String format(LogRecord record)
    {
        StringBuilder msg = new StringBuilder();
        msg.append(this.dateFormat.format(Long.valueOf(record.getMillis())));
        Level lvl = record.getLevel();

        if (lvl == Level.FINEST)
        {
            msg.append(" [FINEST] ");
        }
        else if (lvl == Level.FINER)
        {
            msg.append(" [FINER] ");
        }
        else if (lvl == Level.FINE)
        {
            msg.append(" [FINE] ");
        }
        else if (lvl == Level.INFO)
        {
            msg.append(" [INFO] ");
        }
        else if (lvl == Level.WARNING)
        {
            msg.append(" [WARNING] ");
        }
        else if (lvl == Level.SEVERE)
        {
            msg.append(" [SEVERE] ");
        }
        else if (lvl == Level.SEVERE)
        {
            msg.append(" [" + lvl.getLocalizedName() + "] ");
        }

        msg.append(record.getMessage());
        msg.append(System.lineSeparator());
        Throwable thr = record.getThrown();

        if (thr != null)
        {
            StringWriter thrDump = new StringWriter();
            thr.printStackTrace(new PrintWriter(thrDump));
            msg.append(thrDump.toString());
        }

        return msg.toString();
    }
}

Make FML logs use system line endings for consistency with Java stack traces in the logs.