Fixed Joint added during runtime not showing up in inspector

Hi all, I'm trying to get a fixed joint to add to a gameobject and then attach to another object , but its not showing up in the inspector

Code (csharp):

1.  
2.  
3. void OnCollisionEnter(Collision collision)
4.     {if(true)
5.         {
6.             if (First)
7.             {
8.  
9.       FixedJoint J = gameObject.AddComponent("FixedJoint") as FixedJoint;
10.                 J.connectedBody = collision.rigidbody;
11.                 J.breakForce = 0.01f;
12.                 J.breakTorque = 0.01f;
13.             //    print(gameObject.name);
14.                 First = false;
15.                 print(J.connectedBody.gameObject.name+ "connected too");
16.                 // J.connectedBody = collision.rigidbody;
17.  
18.             }
19.  
20.         }
21.     }
22.  

This line

Code (csharp):

1.  
2.  print(J.connectedBody.gameObject.name+ "connected too");
3.  

works fine and it prints out a name, which would mean the fixed joint is being created . But it doesn't show up in the inspector . Any ideas .