Libraries

• Callng code from other code sources that are not your own, is integrating a dependency into your application.

  • Calling a method in a library that has been imported on to the classpath, is similar to calling a http api endpoint

Benefits

• Reduce writing code over and over again

• Faster response than http call over network, if doing the same thing, as there is network latency

  • although depends if that library calls something over the network (ie it is a client for a service)

• Dependable, as a http service might be down or slow network, but the library is shipped with your code so will always be there

• Algorithms used can be far more efficient and correct than yours, thus reducing time for creating this to spend on app specific code

• Maintains a specific way of doing something

Downsides

• Need to wait for others to update, if there are issues or you need a new feature, or you did it and waiting for it to be added to new version

• Need to manage the versions, issues with transitive dependencies

  • Use of build tools like maven/gradle helps

• If a new version is out, you need to manually update yourself

  • Can have plugins in maven to check for latest

• Can get locked in to libraries if not careful

  • use of clean architecture/ DIP and being very sure that it is necessary for key areas of code base

• Can be massive libraries where you used a few things, leads to code bloat

  • Can copy and paste the code

  • monkey patch

• May need to adapt the code to meet your needs, this can lead to ownership of code (time to learn etc)

• Issues with open source libraries, not maintained, does not meet company polices etc

Creating libraries

check curl library

• Modularise – make the library single purpose

• Ensure that the consumers are local

• Document it well, as though it’s a larger library

• Stop before it gets too diverse/entangled

• Avoid putting service business logic into the library

Links

https://www.javacodegeeks.com/2020/04/the-library-paradox.html