These weeks I have implemented the obstacle avoidance behaviour:
[video]3D Steer Behaviors with Java: Obstacle Avoidance - YouTube
For further details visit: http://jmesteer.bdevel.org/devblog/#d4
As always you can download the demos here: http://jmesteer.bdevel.org/devblog/downloads/SteerDemos_1-8.zip
The next week I will extend the obstacle avoidance to neighbour avoidance.
I forgot to mention that I developed a function to calculate a random vector inside a plane, Maybe can I add it to the jme plane class ?
Here is the code:
[java]
//Generates a random vector inside a plane defined by a normal vector and a point
private Vector3f randomVectInPlane(Vector3f planeNormalV, Vector3f planePoint)
{
Random rand = FastMath.rand;
/* Plane ecuation: Ax + By + Cz + D = 0
* => z = -(Ax + By + D) / C
* => x = -(By + Cz + D) / A
* => y = -(Ax + Cz + D) / B
*/
float a = planeNormalV.x;
float b = planeNormalV.y;
float c = planeNormalV.z;
float d = -(
(a * planePoint.x) +
(b * planePoint.y) +
(c * planePoint.z)
);
float x, y, z;
if(c != 0)
{
x = rand.nextFloat();
y = rand.nextFloat();
z = -((a * x) + (b * y) + d) / c;
}
else if(a != 0)
{
y = rand.nextFloat();
z = rand.nextFloat();
x = -((b * y) + (c * z) + d) / a;
}
else if(b != 0)
{
x = rand.nextFloat();
z = rand.nextFloat();
y = -((a * x) + (c * z) + d) / b;
}
else
{
x = rand.nextFloat();
y = rand.nextFloat();
z = rand.nextFloat();
}
Vector3f randPoint = new Vector3f(x, y, z);
return randPoint.subtract(planePoint);
}
[/java]
Cool stuffs 
Hm that method is indeed quite usefull fo a bunch of other applications.