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leJOS (pronounced like the Spanish word "lejos" for "far") is a tiny Java Virtual Machine. In 2013 it was ported to the LEGO EV3 brick.

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package lejos.hardware.sensor;

import lejos.hardware.port.I2CPort;
import lejos.hardware.port.Port;

/**
 * HiTechnic NXT Acceleration / Tilt Sensor (NAC1040)

 * The HiTechnic Accelerometer / Tilt Sensor measures acceleration in three
 * axes.
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * 
 * Supported modes
Mode name Description unit(s) Getter
Acceleration Measures acceleration over three axes. meter / second²  {@link #getAccelerationMode() }
 * 
 * 
 * 
 * 
 * See 
 *      Sensor Product page  (Some details from HTAC-driver.h from
 *      http://botbench.com/blog/robotc-driver-suite/)
 * 
 * See  The
 *      leJOS sensor framework
 * See {@link lejos.robotics.SampleProvider leJOS conventions for
 *      SampleProviders}
 * 
 *      

 * 
 * 
 * @author Lawrie Griffiths
 * @author Michael Mirwaldt
 * 
 */
public class HiTechnicAccelerometer extends I2CSensor {
  private static final int   BASE_ACCEL = 0x42;
  private static final int   OFF_X_HIGH = 0x00;
  private static final int   OFF_Y_HIGH = 0x01;
  private static final int   OFF_Z_HIGH = 0x02;
  private static final int   OFF_2BITS  = 3;
  private static final float TO_SI      = 0.049033251f;

  private byte[]             buf        = new byte[6];

  /**
   * Creates a SampleProvider for the HiTechnic Acceleration Sensor
   * 
   * @param port
   *          the I2C port
   * @param address
   *          the I2C address of the sensor
   */
  public HiTechnicAccelerometer(I2CPort port, int address) {
    super(port, address);
    init();
  }

  /**
   * Creates a SampleProvider for the HiTechnic Acceleration Sensor
   * 
   * @param port
   *          the I2C port
   */
  public HiTechnicAccelerometer(I2CPort port) {
    this(port, DEFAULT_I2C_ADDRESS);
    init();
  }

  /**
   * Creates a SampleProvider for the HiTechnic Acceleration Sensor
   * 
   * @param port
   *          the sensor port
   * @param address
   *          the I2C address of the sensor
   */
  public HiTechnicAccelerometer(Port port, int address) {
    super(port, address, TYPE_LOWSPEED_9V);
    init();
  }

  /**
   * Creates a SampleProvider for the HiTechnic Acceleration Sensor
   * 
   * @param port
   *          the I2C port
   */
  public HiTechnicAccelerometer(Port port) {
    this(port, DEFAULT_I2C_ADDRESS);
    init();
  }

  protected void init() {
    setModes(new SensorMode[] { new AccelMode() });
  }

  /**
   * HiTechnic NXT Acceleration , Acceleration mode

   * Measures acceleration over three axes.
   * 
   * 

   * Size and content of the sample

   * The sample contains 3 elements, containing acceleration over the X, Y and Z
   * axis respectively. The range of the sensor is -2 to 2 G (1G = 9.81
   * m/s²).
   * 
   * 
   * 
   * @return A sampleProvider
   * See {@link lejos.robotics.SampleProvider leJOS conventions for
   *      SampleProviders}
   * See 
   *      Sensor datasheet 
   */
  public SensorMode getAccelerationMode() {
    return getMode(0);
  }

  private class AccelMode implements SensorMode {

    @Override
    public int sampleSize() {
      return 3;
    }

    @Override
    public void fetchSample(float[] sample, int offset) {
      getData(BASE_ACCEL, buf, 0, 6);

      sample[offset + 0] = ((buf[OFF_X_HIGH] << 2) + (buf[OFF_X_HIGH
          + OFF_2BITS] & 0xFF))
          * TO_SI;
      sample[offset + 1] = ((buf[OFF_Y_HIGH] << 2) + (buf[OFF_Y_HIGH
          + OFF_2BITS] & 0xFF))
          * TO_SI;
      sample[offset + 2] = ((buf[OFF_Z_HIGH] << 2) + (buf[OFF_Z_HIGH
          + OFF_2BITS] & 0xFF))
          * TO_SI;
    }

    @Override
    public String getName() {
      return "Acceleration";
    }
  }
}

Supported modes
Mode name	Description	unit(s)	Getter
Acceleration	Measures acceleration over three axes.	meter / second²	{@link #getAccelerationMode() }