SLF4J API is a simple API that allows to plug in any desired logging library at deployment time.

Here is the source code for SLF4J API 2.0.4. You can download its pre-compiled version slf4j-api-2.0.4.jar at SLF4J Download Website.

⏎ org/slf4j/helpers/SubstituteServiceProvider.java

package org.slf4j.helpers;

import org.slf4j.ILoggerFactory;
import org.slf4j.IMarkerFactory;
import org.slf4j.spi.MDCAdapter;
import org.slf4j.spi.SLF4JServiceProvider;

public class SubstituteServiceProvider implements SLF4JServiceProvider {
    private final SubstituteLoggerFactory loggerFactory = new SubstituteLoggerFactory();
    private final IMarkerFactory markerFactory = new BasicMarkerFactory();
    private final MDCAdapter mdcAdapter = new BasicMDCAdapter();

    @Override
    public ILoggerFactory getLoggerFactory() {
        return loggerFactory;
    }

    public SubstituteLoggerFactory getSubstituteLoggerFactory() {
        return loggerFactory;
    }

    @Override
    public IMarkerFactory getMarkerFactory() {
        return markerFactory;
    }

    @Override
    public MDCAdapter getMDCAdapter() {
        return mdcAdapter;
    }

    @Override
    public String getRequestedApiVersion() {
        throw new UnsupportedOperationException();
    }

    @Override
    public void initialize() {

    }
}

⏎ org/slf4j/helpers/SubstituteServiceProvider.java

Or download all of them as a single archive file:

File name: slf4j-api-2.0.4-sources.jar
File size: 70304 bytes
Release date: 2022-11-17
Download 

⇒ Source Code for SLF4J Simple Logging

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⇑⇑ SLF4J - Simple Logging Facade for Java