It is important not to select a library for use that is not alive. Have a look at the roadmap of the library, the last time a release was shipped, and the frequency of the commits. If the library is not alive, we should consider not using it. Libraries work in an environment and the environment changes. The library may connect to a database. The new version of the database may provide new features that give us better performance only if the library is modified to accommodate these new features. The library communicates over HTTP; will it support the new 2.0 version of the protocol? If nothing else, the version of the Java environment will change over the years and the library we use should sooner or later follow it to leverage the new features.

There is no guarantee that an alive library will always stay alive. However, a library that is already dead will certainly not resurrect.

Even if the project is alive at the moment, there are some points that may give some hints about the future of the library. If the company developing it is well-established and financially stable, and the library is developed with a reasonable business model, then there is a low risk that the project dies. If there are a lot of companies who use the library, then it is likely that the project will stay alive even if the original team stops working on it or the original financing structure changes. However, these are only small factors and not well-established facts. There is no guarantee, and telling the future is more an art than a science.