does all tags defined in POJO need assign a value?

I created a POJO to insert into influxdb:

@Measurement(name = "mymeasurement")
public class Pojo {

@Column(name = "tag1", tag =true)
private string tag1;

@Column(name = "tag2", tag = true)
private String tag2;

@Column(name = "value")
private Double value;

public String getTag1() {
  return tag1;
}

public void setTag1(String tag) {
  this.tag1 = tag;
}

public String getTag2() {
  return tag2;
}

public void setTag2(String tag) {
  this.tag2 = tag;
}

public Double getValue() {
  return value;
}

public void setDoubleObject(Double v) {
  this.value = v;
}

}

when i create a object with out set all tags, it failed with null exception:

Pojo pojo = new Pojo();
pojo.SetTag1("tag1value");
pojo.setValue(1);

Long t = Instant.now().toEpochMilli();
Point point = Point.measurementByPOJO(pojo.getClass()).addFieldsFromPOJO(pojo).time(t,TimeUnit.MILLISECONDS).build();

influxDb.write(getDBName(), getRPName(), point);

java.lang.NullPointerException

     at org.influxdb.dto.Point.escapeKey(Point.java:471)

     at org.influxdb.dto.Point.concatenatedTags(Point.java:432)

     at org.influxdb.dto.Point.lineProtocol(Point.java:420)

my question is does all tag need to be assign a value?

Start with Point.java at escapeKey, concatenatedTags, and lineProtocol, then trace how addFieldsFromPOJO handles the unset tag2 field. Check existing tests around POJO tags and line-protocol generation; done means the expected behavior for an unset tag is defined and covered without the reported NullPointerException.