Packages 
Package Description
io.opentelemetry.api
The OpenTelemetry API.
io.opentelemetry.api.baggage
API for associating entries with scoped operations.
io.opentelemetry.api.baggage.propagation
Default OpenTelemetry remote baggage propagators.
io.opentelemetry.api.common
This package contains code common across the OpenTelemetry APIs, including Attributes and classes/utilities for interacting with them.
io.opentelemetry.api.internal
Interfaces and implementations that are internal to OpenTelemetry.
io.opentelemetry.api.metrics
This package describes the Metrics API that can be used to record application Metrics.
io.opentelemetry.api.metrics.spi
The SPI (service provider interface) for initializing the OpenTelemetry metrics API.
io.opentelemetry.api.spi  
io.opentelemetry.api.trace
API for distributed tracing.
io.opentelemetry.api.trace.attributes
OpenTelemetry semantic attributes.
io.opentelemetry.api.trace.propagation
Default OpenTelemetry remote trace propagators.
io.opentelemetry.api.trace.spi
The SPI (service provider interface) for initializing the OpenTelemetry tracing API.