public Builder clear() {
        super.clear();
        tag_ = 0L;
        bitField0_ = (bitField0_ & ~0x00000001);
        restitution_ = 0F;
        bitField0_ = (bitField0_ & ~0x00000002);
        friction_ = 0F;
        bitField0_ = (bitField0_ & ~0x00000004);
        density_ = 0F;
        bitField0_ = (bitField0_ & ~0x00000008);
        sensor_ = false;
        bitField0_ = (bitField0_ & ~0x00000010);
        if (filterBuilder_ == null) {
          filter_ = org.box2d.proto.Box2D.PbFilter.getDefaultInstance();
        } else {
          filterBuilder_.clear();
        }
        bitField0_ = (bitField0_ & ~0x00000020);
        if (shapeBuilder_ == null) {
          shape_ = org.box2d.proto.Box2D.PbShape.getDefaultInstance();
        } else {
          shapeBuilder_.clear();
        }
        bitField0_ = (bitField0_ & ~0x00000040);
        return this;
      }