Here's an example of a simple Bluetooth Android application in Java. This example demonstrates how to discover nearby Bluetooth devices and establish a connection with one of them.
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;