com.badlogic.gdx.physics.box2d
Interfaces 
ContactFilter
ContactListener
DestructionListener
QueryCallback
RayCastCallback
Classes 
Body
BodyDef
Box2DDebugRenderer
ChainShape
CircleShape
Contact
ContactImpulse
EdgeShape
Filter
Fixture
FixtureDef
Joint
JointDef
JointEdge
Manifold
MassData
PolygonShape
Shape
Transform
World
WorldManifold
Enums 
BodyDef.BodyType
JointDef.JointType
Manifold.ManifoldType
Shape.Type