Why is my JPQL not working?

Question

This JPQL used to work but then it broke for no reason. I now get this strange exception:

java.lang.IllegalArgumentException: Parameter "Parameter<LandKod>('landKod')" declared in "SELECT r FROM Region r WHERE r.landKod = :landKod" is set to value of "US" of type "java.lang.String", but this parameter is bound to a field of type "se.prv.pandora.arendeprocess.entity.LandKod".

which seems to indicate that there is some kind of name conflict of what is named landKod in my code. Here is the source:

import java.io.Serializable;

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;

@Entity(name = "Region")
@Table(name="TP197_REGION")

@NamedQueries({
    @NamedQuery(name = "getAllValidRegions", query = "SELECT r FROM Region r WHERE r.histKod = 'A'"), 
    @NamedQuery(name = "getRegionsByLandkod", query = "SELECT r FROM Region r WHERE r.landKod = :landKod")
})

public class Region implements Serializable {

    @Id
    private int regionId;

    @ManyToOne
    @JoinColumn(name="landKod", referencedColumnName="landKod")
    private LandKod landKod ;

    private String histKod ;
    private String regionForkort;
    private String regionRubrik;
    private String regionBeskr;

    public Region() {
        super();
    }


    public int getRegionId() {
        return regionId;
    }


    public void setRegionId(int regionId) {
        this.regionId = regionId;
    }


    public String getRegionForkort() {
        return regionForkort;
    }

    public void setRegionForkort(String regionForkort) {
        this.regionForkort = regionForkort;
    }

    public String getRegionRubrik() {
        return regionRubrik;
    }

    public void setRegionRubrik(String regionRubrik) {
        this.regionRubrik = regionRubrik;
    }

    public String getRegionBeskr() {
        return regionBeskr;
    }

    public void setRegionBeskr(String regionBeskr) {
        this.regionBeskr = regionBeskr;
    }


    public String getHistKod() {
        return histKod;
    }


    public void setHistKod(String histKod) {
        this.histKod = histKod;
    }


    public String getRegionFormatted() {
        if(regionForkort!=null && regionForkort.length()>0) {
            return regionForkort + " " + regionRubrik;
        } else {
            return regionRubrik;

        }
    }


    public LandKod getLandKod() {
        return landKod;
    }


    public void setLandKod(LandKod landKod) {
        this.landKod = landKod;
    }


}

Here's the method implementation where it allows a string as a parameter:

@Override
public List<Region> getRegionsByLandkod(String landKod) {

    List<Region> regionsList = null;


try {

    Query query = em.createNamedQuery("getRegionsByLandkod");
    query.setParameter("landKod", landKod);
    regionsList =  (List<Region>) query.getResultList();

} catch(Exception e){ 
    logger.info("Kunde inte hitta någon region med landkod: "+landKod, e);
}

return regionsList;
}

Could you help me fix this error?

Answer 1

It seems you're calling getRegionsByLandkod with a String instead of a LandKod object. Verify where you use this query if the parameter is correct.