public org.box2d.proto.Box2D.PbJoint buildPartial() {
        org.box2d.proto.Box2D.PbJoint result = new org.box2d.proto.Box2D.PbJoint(this);
        int from_bitField0_ = bitField0_;
        int from_bitField1_ = bitField1_;
        int to_bitField0_ = 0;
        int to_bitField1_ = 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;
        }
        result.bodyA_ = bodyA_;
        if (((from_bitField0_ & 0x00000008) == 0x00000008)) {
          to_bitField0_ |= 0x00000008;
        }
        result.bodyB_ = bodyB_;
        if (((from_bitField0_ & 0x00000010) == 0x00000010)) {
          to_bitField0_ |= 0x00000010;
        }
        result.collideConnected_ = collideConnected_;
        if (((from_bitField0_ & 0x00000020) == 0x00000020)) {
          to_bitField0_ |= 0x00000020;
        }
        if (localAnchorABuilder_ == null) {
          result.localAnchorA_ = localAnchorA_;
        } else {
          result.localAnchorA_ = localAnchorABuilder_.build();
        }
        if (((from_bitField0_ & 0x00000040) == 0x00000040)) {
          to_bitField0_ |= 0x00000040;
        }
        if (localAnchorBBuilder_ == null) {
          result.localAnchorB_ = localAnchorB_;
        } else {
          result.localAnchorB_ = localAnchorBBuilder_.build();
        }
        if (((from_bitField0_ & 0x00000080) == 0x00000080)) {
          to_bitField0_ |= 0x00000080;
        }
        result.refAngle_ = refAngle_;
        if (((from_bitField0_ & 0x00000100) == 0x00000100)) {
          to_bitField0_ |= 0x00000100;
        }
        result.enableLimit_ = enableLimit_;
        if (((from_bitField0_ & 0x00000200) == 0x00000200)) {
          to_bitField0_ |= 0x00000200;
        }
        result.lowerLimit_ = lowerLimit_;
        if (((from_bitField0_ & 0x00000400) == 0x00000400)) {
          to_bitField0_ |= 0x00000400;
        }
        result.upperLimit_ = upperLimit_;
        if (((from_bitField0_ & 0x00000800) == 0x00000800)) {
          to_bitField0_ |= 0x00000800;
        }
        result.enableMotor_ = enableMotor_;
        if (((from_bitField0_ & 0x00001000) == 0x00001000)) {
          to_bitField0_ |= 0x00001000;
        }
        result.motorSpeed_ = motorSpeed_;
        if (((from_bitField0_ & 0x00002000) == 0x00002000)) {
          to_bitField0_ |= 0x00002000;
        }
        result.maxMotorTorque_ = maxMotorTorque_;
        if (((from_bitField0_ & 0x00004000) == 0x00004000)) {
          to_bitField0_ |= 0x00004000;
        }
        if (localAxisABuilder_ == null) {
          result.localAxisA_ = localAxisA_;
        } else {
          result.localAxisA_ = localAxisABuilder_.build();
        }
        if (((from_bitField0_ & 0x00008000) == 0x00008000)) {
          to_bitField0_ |= 0x00008000;
        }
        result.maxMotorForce_ = maxMotorForce_;
        if (((from_bitField0_ & 0x00010000) == 0x00010000)) {
          to_bitField0_ |= 0x00010000;
        }
        result.length_ = length_;
        if (((from_bitField0_ & 0x00020000) == 0x00020000)) {
          to_bitField0_ |= 0x00020000;
        }
        result.frequency_ = frequency_;
        if (((from_bitField0_ & 0x00040000) == 0x00040000)) {
          to_bitField0_ |= 0x00040000;
        }
        result.dampingRatio_ = dampingRatio_;
        if (((from_bitField0_ & 0x00080000) == 0x00080000)) {
          to_bitField0_ |= 0x00080000;
        }
        if (groundAnchorABuilder_ == null) {
          result.groundAnchorA_ = groundAnchorA_;
        } else {
          result.groundAnchorA_ = groundAnchorABuilder_.build();
        }
        if (((from_bitField0_ & 0x00100000) == 0x00100000)) {
          to_bitField0_ |= 0x00100000;
        }
        if (groundAnchorBBuilder_ == null) {
          result.groundAnchorB_ = groundAnchorB_;
        } else {
          result.groundAnchorB_ = groundAnchorBBuilder_.build();
        }
        if (((from_bitField0_ & 0x00200000) == 0x00200000)) {
          to_bitField0_ |= 0x00200000;
        }
        result.lengthA_ = lengthA_;
        if (((from_bitField0_ & 0x00400000) == 0x00400000)) {
          to_bitField0_ |= 0x00400000;
        }
        result.lengthB_ = lengthB_;
        if (((from_bitField0_ & 0x00800000) == 0x00800000)) {
          to_bitField0_ |= 0x00800000;
        }
        result.ratio_ = ratio_;
        if (((from_bitField0_ & 0x01000000) == 0x01000000)) {
          to_bitField0_ |= 0x01000000;
        }
        result.maxLengthA_ = maxLengthA_;
        if (((from_bitField0_ & 0x02000000) == 0x02000000)) {
          to_bitField0_ |= 0x02000000;
        }
        result.maxLengthB_ = maxLengthB_;
        if (((from_bitField0_ & 0x04000000) == 0x04000000)) {
          to_bitField0_ |= 0x04000000;
        }
        if (targetBuilder_ == null) {
          result.target_ = target_;
        } else {
          result.target_ = targetBuilder_.build();
        }
        if (((from_bitField0_ & 0x08000000) == 0x08000000)) {
          to_bitField0_ |= 0x08000000;
        }
        result.maxForce_ = maxForce_;
        if (((from_bitField0_ & 0x10000000) == 0x10000000)) {
          to_bitField0_ |= 0x10000000;
        }
        result.joint1_ = joint1_;
        if (((from_bitField0_ & 0x20000000) == 0x20000000)) {
          to_bitField0_ |= 0x20000000;
        }
        result.joint2_ = joint2_;
        if (((from_bitField0_ & 0x40000000) == 0x40000000)) {
          to_bitField0_ |= 0x40000000;
        }
        result.springFrequency_ = springFrequency_;
        if (((from_bitField0_ & 0x80000000) == 0x80000000)) {
          to_bitField0_ |= 0x80000000;
        }
        result.springDampingRatio_ = springDampingRatio_;
        if (((from_bitField1_ & 0x00000001) == 0x00000001)) {
          to_bitField1_ |= 0x00000001;
        }
        result.maxTorque_ = maxTorque_;
        if (((from_bitField1_ & 0x00000002) == 0x00000002)) {
          to_bitField1_ |= 0x00000002;
        }
        result.maxLength_ = maxLength_;
        if (((bitField1_ & 0x00000004) == 0x00000004)) {
          bodies_ = java.util.Collections.unmodifiableList(bodies_);
          bitField1_ = (bitField1_ & ~0x00000004);
        }
        result.bodies_ = bodies_;
        if (((bitField1_ & 0x00000008) == 0x00000008)) {
          joints_ = java.util.Collections.unmodifiableList(joints_);
          bitField1_ = (bitField1_ & ~0x00000008);
        }
        result.joints_ = joints_;
        if (((from_bitField1_ & 0x00000010) == 0x00000010)) {
          to_bitField1_ |= 0x00000004;
        }
        result.targetVolume_ = targetVolume_;
        result.bitField0_ = to_bitField0_;
        result.bitField1_ = to_bitField1_;
        onBuilt();
        return result;
      }