MOC — General Utility Libraries

Cross-cutting libraries used throughout the codebase: one per language. These sit beneath
every other subsystem MOC (container-jdisc, content-nodes, config-admin).
(Description from vespa/Code-map.md; sizes from first-hand inspection.)

Modules

• vespa/vespalib — general utility library for C++ (1174 files, ~123k LOC). Observed
  subdirs include data/, net/, searchlib/, geometry/, parse/, objects/,
  testkit/ — a wide-scope “std-plus” layer.
• vespajlib — general utility library for Java, including the Java tensor library
  implementation (577 files, ~68k LOC).

Note: the Java tensor implementation lives here (vespajlib) while the C++ tensor/eval
library is its own module under content-nodes (vespa/eval).

Anchor files

• vespa/vespalib/data/ — core data structures (observed directory; incl. abi-spec.json,
  suggesting a stable ABI surface).
• vespa/vespalib/src/vespa/vespalib/ — main C++ source tree.
• vespa/vespajlib/src/main/java/com/yahoo/tensor/ — Java tensor library (path pattern
  observed; exact subpackage to verify).

Open questions

• Verify the vespajlib tensor package path and pick the canonical “first file to read”.
• Should other low-level modules (fnet, flags, jrt, http-utils, fsa) be folded in?
• What is the ABI-compatibility policy signaled by vespa/vespalib/data/abi-spec.json?