Eclipse IDE showing error for Composite Primary Key classes in JPA

calvin.mk :

I have an Entity class with composite PK as below:
using @Embeddable and @EmbeddedId annotations.

/** The primary key class for the uom_conversion database table. */
@Embeddable
public class UomConversionPK implements Serializable {
    private static final long serialVersionUID = 1L;

    @Column(name="product_id", insertable=false, updatable=false)
    private int productId;

    @Column(name="base_uom_id", insertable=false, updatable=false)
    private int baseUomId;

    @Column(name="to_unit_id", insertable=false, updatable=false)
    private int toUnitId;
    //getters, setters
}

And the Entity which is using it is:

/** The persistent class for the uom_conversion database table. */
@Entity
@Table(name="uom_conversion")
public class UomConversion implements Serializable {
    private static final long serialVersionUID = 1L;

    @EmbeddedId
    private UomConversionPK id;
}

Here Eclipse is displaying error: "UomConversionPK cannot be resolved to a type"

In another project I'm using Entities with composite PK without any errors.

Now this seems to be a JPA facet problem, wondering why Eclipse is not able to resolve UomConversionPK or am I doing something wrong ?

Swetha N :

Well this error do occur sometimes for @EmbeddedId annotation, though not always, when creating JPA entities from tables using JPA Tools.

In my case this problem was not resolved until I set the following to Ignore and then back to Error:
Windows -> Preferences -> Java Persistence -> JPA -> Errors/Warnings -> Embedded ID classes should implement hashcode() and equals(). This error occurs even if Embeddable class do have hashcode() and equals() method implementation. May be this works for you as well.