Great question! It’s easy to miss that DEX files impose the same 65536 reference limit on fields as they do on methods—here’s a clear breakdown of what’s going on:

Why You’re Seeing the Field Reference Error #

First, let’s clarify: the 65536 limit (2^16) applies to both method references and field references in a single DEX file. This hard cap comes from how DEX files are structured:

• DEX uses 16-bit indices to store entries in its method_ids and field_ids tables. Since 16 bits can only represent up to 65536 unique values, each category (methods and fields) hits this limit once you exceed that number of references.

Your error "Too many field references: 131000; max is 65536" means the total number of field references across your app and its dependencies has crossed that 65536 threshold—this includes:

• Fields you’ve defined in your own code
• Fields from third-party libraries you’re using
• Even generated fields (like those from annotation processors or resource IDs)

Why the Documentation Might Have Been Hard to Find #

You’re not alone in this confusion! Android’s official docs sometimes frame this limit as a "method reference limit" in casual explanations, but if you dig deeper, they do explicitly mention fields are included. For example, in the Multidex documentation, it’s stated that Multidex is required when "the total number of references to methods and fields in your app's DEX files exceeds 65536"—the limit applies equally to both.

How to Fix This #

To resolve the field reference overflow, you have a few standard options:

• Enable Multidex: Split your app’s code into multiple DEX files, each staying under the 65536 limit. This is straightforward for apps targeting API level 21+ (Multidex is enabled by default) or older (you’ll need to add the multidex dependency and update your app configuration).
• Optimize Dependencies: Remove unused libraries or use lighter alternatives to cut down on total field references.
• Use R8/ProGuard: Enable code shrinking and obfuscation to eliminate unused fields and reduce the overall reference count.

内容的提问来源于stack exchange，提问作者Orest Savchak