public org.box2d.proto.Box2D.PbBody buildPartial() {
        org.box2d.proto.Box2D.PbBody result = new org.box2d.proto.Box2D.PbBody(this);
        int from_bitField0_ = bitField0_;
        int to_bitField0_ = 0;
        if (((from_bitField0_ & 0x00000001) == 0x00000001)) {
          to_bitField0_ |= 0x00000001;
        }
        result.tag_ = tag_;
        if (((from_bitField0_ & 0x00000002) == 0x00000002)) {
          to_bitField0_ |= 0x00000002;
        }
        result.type_ = type_;
        if (((from_bitField0_ & 0x00000004) == 0x00000004)) {
          to_bitField0_ |= 0x00000004;
        }
        if (positionBuilder_ == null) {
          result.position_ = position_;
        } else {
          result.position_ = positionBuilder_.build();
        }
        if (((from_bitField0_ & 0x00000008) == 0x00000008)) {
          to_bitField0_ |= 0x00000008;
        }
        result.angle_ = angle_;
        if (((from_bitField0_ & 0x00000010) == 0x00000010)) {
          to_bitField0_ |= 0x00000010;
        }
        if (linearVelocityBuilder_ == null) {
          result.linearVelocity_ = linearVelocity_;
        } else {
          result.linearVelocity_ = linearVelocityBuilder_.build();
        }
        if (((from_bitField0_ & 0x00000020) == 0x00000020)) {
          to_bitField0_ |= 0x00000020;
        }
        result.angularVelocity_ = angularVelocity_;
        if (((from_bitField0_ & 0x00000040) == 0x00000040)) {
          to_bitField0_ |= 0x00000040;
        }
        if (forceBuilder_ == null) {
          result.force_ = force_;
        } else {
          result.force_ = forceBuilder_.build();
        }
        if (((from_bitField0_ & 0x00000080) == 0x00000080)) {
          to_bitField0_ |= 0x00000080;
        }
        result.torque_ = torque_;
        if (((from_bitField0_ & 0x00000100) == 0x00000100)) {
          to_bitField0_ |= 0x00000100;
        }
        result.mass_ = mass_;
        if (((from_bitField0_ & 0x00000200) == 0x00000200)) {
          to_bitField0_ |= 0x00000200;
        }
        result.i_ = i_;
        if (((from_bitField0_ & 0x00000400) == 0x00000400)) {
          to_bitField0_ |= 0x00000400;
        }
        result.linearDamping_ = linearDamping_;
        if (((from_bitField0_ & 0x00000800) == 0x00000800)) {
          to_bitField0_ |= 0x00000800;
        }
        result.angularDamping_ = angularDamping_;
        if (((from_bitField0_ & 0x00001000) == 0x00001000)) {
          to_bitField0_ |= 0x00001000;
        }
        result.gravityScale_ = gravityScale_;
        if (((from_bitField0_ & 0x00002000) == 0x00002000)) {
          to_bitField0_ |= 0x00002000;
        }
        result.bullet_ = bullet_;
        if (((from_bitField0_ & 0x00004000) == 0x00004000)) {
          to_bitField0_ |= 0x00004000;
        }
        result.allowSleep_ = allowSleep_;
        if (((from_bitField0_ & 0x00008000) == 0x00008000)) {
          to_bitField0_ |= 0x00008000;
        }
        result.awake_ = awake_;
        if (((from_bitField0_ & 0x00010000) == 0x00010000)) {
          to_bitField0_ |= 0x00010000;
        }
        result.active_ = active_;
        if (((from_bitField0_ & 0x00020000) == 0x00020000)) {
          to_bitField0_ |= 0x00020000;
        }
        result.fixedRotation_ = fixedRotation_;
        if (fixturesBuilder_ == null) {
          if (((bitField0_ & 0x00040000) == 0x00040000)) {
            fixtures_ = java.util.Collections.unmodifiableList(fixtures_);
            bitField0_ = (bitField0_ & ~0x00040000);
          }
          result.fixtures_ = fixtures_;
        } else {
          result.fixtures_ = fixturesBuilder_.build();
        }
        result.bitField0_ = to_bitField0_;
        onBuilt();
        return result;
      }