SmartGattLib is a Java library that simplifies the work with Bluetooth SMART devices (a.k.a. Bluetooth Low Energy in Bluetooth 4.0). It provides all UUIDs of the adopted GATT specification and an convenient way to interpret the characteristics (e.g. Heart Rate, BatteryLevel).
This library allows for easy access to a Bluetooth LE device's AdRecord and RSSI value. It offers additional functionality for iBeacons.
android-btxfr is a lightweight library designed to send and receive any type of data between Android (API 15 and higher). It can be used to exchange text, files, photos, videos, sounds, and literally any other type of binary data. The library supports anything that can be put into a byte stream and includes digest checking to ensure data integrity.
Bluetooth Serial Port Profile which comfortable to developer application to communication with micro-controller or android device via bluetooth. This library include all important methods for serial port profile on bluetooth communication. It has built-in bluetooth device list.
This library allows you to easily create a socket bluetooth connection for two android devices with one server and one client. This library is compatible with the Android SDK 2.3 to 4.4.