Force slf4j to use logback

Question

Is there anyway to force slf4j to use specific logging provider (logback in my case)? As in their docs:

Multiple bindings were found on the class path

Answer 1

Generally your own code is at the beginning of the classpath. Because of this, one way to do it is to create your own org.slf4j.impl.StaticLoggerBinder class:

package org.slf4j.impl;

import org.slf4j.ILoggerFactory;
import org.slf4j.spi.LoggerFactoryBinder;

/**
 * Force tests to use JDK14 for logging.
 */
@SuppressWarnings("UnusedDeclaration")
public class StaticLoggerBinder implements LoggerFactoryBinder {
    private static final StaticLoggerBinder SINGLETON = new StaticLoggerBinder();

    public static String REQUESTED_API_VERSION = "1.6";

    public static final StaticLoggerBinder getSingleton() {
      return SINGLETON;
    }

    private StaticLoggerBinder() {
    }

    @Override
    public ILoggerFactory getLoggerFactory() {
        return new JDK14LoggerFactory();
    }

    @Override
    public String getLoggerFactoryClassStr() {
        return "org.slf4j.impl.JDK14LoggerFactory";
    }
}

Answer 2

Other than cleaning up your class path, there is no way to force SLF4J to bind with a given implementation.