TerebonkCore is a merged API consisting of two neat libraries - BridJ(click to view license) and SLF4J(click to view license).
To experience this power, just drop it to your mods folder and here you are.
However, this is more for developers than for ordinary users.

BridJ
BridJ is a Java / native interoperability library that focuses on speed and ease of use.

It is similar in spirit to JNA (dynamic bindings that don't require any native compilation, unlike JNI), but was designed to support C++, to be blazing fast (thanks to dyncall + hand-optimized assembly tweaks) and to use modern Java features.

A comprehensive documentation is available on its Wiki (needs migration to GitHub Pages!).

Simple Logging Facade for Java (SLF4J)

The Simple Logging Facade for Java (SLF4J) serves as a simple facade or abstraction for various logging frameworks (e.g. java.util.logging, logback, log4j) allowing the end user to plug in the desired logging framework at deployment time.

Before you start using SLF4J, we highly recommend that you read the two-page SLF4J user manual.

Note that SLF4J-enabling your library implies the addition of only a single mandatory dependency, namely slf4j-api.jar. If no binding is found on the class path, then SLF4J will default to a no-operation implementation.

In case you wish to migrate your Java source files to SLF4J, consider our migrator tool which can migrate your project to use the SLF4J API in just a few minutes.

In case an externally-maintained component you depend on uses a logging API other than SLF4J, such as commons logging, log4j or java.util.logging, have a look at SLF4J's binary-support for legacy APIs.