How to get the DiscriminatorValue at run time

I can imagine few cases where it might be helpful, but despite the reason why you need this, you could create on your abstract class method like

@Transient
public String getDiscriminatorValue(){
    DiscriminatorValue val = this.getClass().getAnnotation( DiscriminatorValue.class );

    return val == null ? null : val.value();
}

You can map your discriminator as a read-only property:

public class ApplicationProcess { 

    ...

    @Column(name = "apType", insertable = false, updatable = false)
    private String apType;

}