Guava -> The JDK Std library, unless you need more performant collections provided by it. Guice -> If you need to support the jakarta.* namespace the only real

Guava -> The JDK Std library, unless you need more performant collections provided by it. Guice -> If you need to support the jakarta.* namespace the only real answer is Weld or another CDI compliant implementation. Otherwise guice is probably still fine. GSON -> Jackson as always.