Android : Camera camera=Camera.open(); Why it is wrong to write separately?

Camera  camera=Camera.open();  //that's Right,but if you write separately, it's wrong

Camera  camera;
camera=Camera.open();

//reason: Syntax error on token ";", , expected

//and 

Camera  camera=Camera.open();

camera.release(); //this place It's wrong,WHY???

public void onClick(View V)
{

     camera.release(); //but this place is right

}