A bit of example code that routes logging from Jsch to SLF4j (using Java 8)

JSch logging

import java.util.HashMap;
import java.util.function.BooleanSupplier;
import java.util.function.Consumer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.jcraft.jsch.JSch;

/**
 * Demonstrates enabling and routing JSch (http://www.jcraft.com/jsch/) logging
 * into SLF4J (http://www.slf4j.org/) logging using Java 8
 *
 * @author <a href="mailto:[email protected]">Dan Armbrust</a>
 */
public class DemoSnippit
{
	private static Logger log = LoggerFactory.getLogger(DemoSnippit.class);

	public DemoSnippit()
	{
		JSch.setLogger(new com.jcraft.jsch.Logger()
		{
			private HashMap<Integer, Consumer<String>> logMap = new HashMap<>();
			private HashMap<Integer, BooleanSupplier> enabledMap = new HashMap<>();

			{
				logMap.put(com.jcraft.jsch.Logger.DEBUG, log::debug);
				logMap.put(com.jcraft.jsch.Logger.ERROR, log::error);
				logMap.put(com.jcraft.jsch.Logger.FATAL, log::error);
				logMap.put(com.jcraft.jsch.Logger.INFO, log::info);
				logMap.put(com.jcraft.jsch.Logger.WARN, log::warn);

				enabledMap.put(com.jcraft.jsch.Logger.DEBUG, log::isDebugEnabled);
				enabledMap.put(com.jcraft.jsch.Logger.ERROR, log::isErrorEnabled);
				enabledMap.put(com.jcraft.jsch.Logger.FATAL, log::isErrorEnabled);
				enabledMap.put(com.jcraft.jsch.Logger.INFO, log::isInfoEnabled);
				enabledMap.put(com.jcraft.jsch.Logger.WARN, log::isWarnEnabled);
			}

			@Override
			public void log(int level, String message)
			{
				logMap.get(level).accept(message);
			}

			@Override
			public boolean isEnabled(int level)
			{
				return enabledMap.get(level).getAsBoolean();
			}
		});
	}
}