Question

All java libraries are not present within android e.g. javax.script, java.awt.* etc. It makes it very difficult to use a lot of useful libraries written in java (e.g. libraries for java script evaluation, image processing, etc.).

I am just curious, would anyone have an idea as to why android team has decided to keep these out of android sdk?

Answer 1

This article might provide some basic explanation:

Google’s mobile phone platform, Android, supports a relatively large
subset of the Java Standard Edition 5.0 library. Some things were left
out because they simply didn’t make sense (like printing), and others
because better APIs are available that are specific to Android (like
user interfaces).

I think that other reasons might include the fact that the mobile platform does not have the computational resources that other devices such as laptops and desktops might have (even though this seems to be changing with the introduction of high end mobile phones).

Edit: I think that the concept of ‘usefulness’ varies, so what yourself find useful might not be so for other people. If you want specific reasons why this specific package was left out, it is of my opinion that you are asking it in the wrong place. With regards to this specific package, the javax.script, you might want to consider taking a look at this previous SO post which proposes an alternative.