16:50:36.689 [main] WARN  org.hibernate.type.descriptor.java.JavaTypeDescriptorRegistry - HHH000481: Encountered Java type [class FooConverter] for which we could not locate a JavaTypeDescriptor and which does not appear to implement equals and/or hashCode.  This can lead to significant performance problems when performing equality/dirty checking involving this Java type.  Consider registering a custom JavaTypeDescriptor or at least implementing equals/hashCode.
16:50:36.710 [main] WARN  org.hibernate.type.spi.TypeConfiguration$Scope - HHH000233: Scoping types to session factory org.hibernate.internal.SessionFactoryImpl@261ddbf5 after already scoped org.hibernate.internal.SessionFactoryImpl@261ddbf5

@Entity(name = "Entity")
public class Entity {
    @Id
    @Column(name = "id")
    public String id;

    @NotNull
    @Column(name = "foo")
    @Convert(converter = FooConverter.class)
    public Foo foo;
}

public enum Foo {
    BAR_1,
    BAR_2,
}

public class FooConverter implements AttributeConverter<Foo, String> {
    private static Map<Foo, String> typeMapping;
    static {
        typeMapping = new EnumMap<>(Foo.class);
        typeMapping.put(Foo.BAR_1, "baa_1");
        typeMapping.put(Foo.BAR_2, "baa_2");
    }

    @Override
    public String convertToDatabaseColumn(Foo t) {
        return typeMapping.get(t);
    }

    @Override
    public Foo convertToEntityAttribute(String s) {
        for (Map.Entry<typeMapping, String> entry : typeMapping.entrySet()) {
            if (entry.getValue().equalsIgnoreCase(s)) {
                return entry.getKey();
            }
        }

        throw new IllegalArgumentException("Invalid value for enum: " + s);
    }
}