What is the purpose of jumboMode in dexOptions for

问题:

According to this post it allows a larger number of strings in the dex files but I don't really understand what it means and the impact on builds.

回答1:

Jumbo mode pertains to the number of strings that can be referenced in a DEX file, which by default are indexed using 16 bit wide integers. Therefore, if your application encodes more than 2^16 strings, the dx tool will fail as well. For string references however, there is a remedy: DEX supports “jumbo opcodes” which allow for 32 bit wide string references. The jumboMode flag in an Android Gradle build script enables this mode, allowing up to 2^32 strings to be referenced.

What this means is if you have more than 2^16 references in your dex files, you can use jumboMode to accommodate for this by allowing up to 2^32 references. This is done by forcing the byte code to always use "jumbo strings" (2^32) references to help avoid issues when merging dex files.

Note: this does NOT have anything to do with the number of method references, so this mode doesn't solve when your dex file has more than 64k methods.

Source: https://developers.soundcloud.com/blog/congratulations-you-have-a-lot-of-code-remedying-androids-method-limit-part-1

In my experiences, this shouldn't have any noticeable impact on builds other than a potential increase in build time.