Polishing.

Use structured NullsPrecedence rendering in JPQL renderer.

Throw UnsupportedOperationException for the time being until Nulls Precedence is supported through Criteria API.

See #3529

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/JpqlQueryRenderer.java

@@ -796,7 +796,7 @@ class JpqlQueryRenderer extends JpqlBaseVisitor<QueryTokenStream> {
 			builder.append(QueryTokens.expression(ctx.DESC()));
 		}
 
-		if(ctx.nullsPrecedence() != null) {
+		if (ctx.nullsPrecedence() != null) {
 			builder.append(visit(ctx.nullsPrecedence()));
 		}
 
@@ -805,8 +805,18 @@ class JpqlQueryRenderer extends JpqlBaseVisitor<QueryTokenStream> {
 
 	@Override
 	public QueryTokenStream visitNullsPrecedence(NullsPrecedenceContext ctx) {
-//		return QueryTokenStream.concat(ctx.children, it-> QueryRendererBuilder.from(QueryTokens.token(it.getText())), TOKEN_SPACE);
-		return QueryTokenStream.justAs(ctx.children, it-> QueryTokens.token(it.getText()));
+
+		QueryRendererBuilder builder = QueryRenderer.builder();
+
+		builder.append(TOKEN_NULLS);
+
+		if (ctx.FIRST() != null) {
+			builder.append(TOKEN_FIRST);
+		} else if (ctx.LAST() != null) {
+			builder.append(TOKEN_LAST);
+		}
+
+		return builder;
 	}
 
 	@Override

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/QueryUtils.java

@@ -753,6 +753,10 @@ public abstract class QueryUtils {
 		PropertyPath property = PropertyPath.from(order.getProperty(), from.getJavaType());
 		Expression<?> expression = toExpressionRecursively(from, property);
 
+		if (order.getNullHandling() != Sort.NullHandling.NATIVE) {
+			throw new UnsupportedOperationException("Applying Null Precedence using Criteria Queries is not yet supported.");
+		}
+
 		if (order.isIgnoreCase() && String.class.equals(expression.getJavaType())) {
 			Expression<String> upper = cb.lower((Expression<String>) expression);
 			return order.isAscending() ? cb.asc(upper) : cb.desc(upper);

spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/QueryUtilsIntegrationTests.java

@@ -15,11 +15,9 @@
  */
 package org.springframework.data.jpa.repository.query;
 
-import static java.util.Collections.singletonList;
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.mockito.Mockito.doReturn;
-import static org.mockito.Mockito.times;
-import static org.mockito.Mockito.verify;
+import static java.util.Collections.*;
+import static org.assertj.core.api.Assertions.*;
+import static org.mockito.Mockito.*;
 
 import jakarta.persistence.Entity;
 import jakarta.persistence.EntityManager;
@@ -48,6 +46,7 @@ import java.util.stream.Collectors;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mockito;
+
 import org.springframework.data.domain.Sort;
 import org.springframework.data.domain.Sort.Direction;
 import org.springframework.data.jpa.domain.sample.Category;
@@ -315,6 +314,20 @@ class QueryUtilsIntegrationTests {
 		assertThat(orders).hasSize(1);
 	}
 
+	@Test // GH-3529
+	void nullPrecedenceThroughCriteriaApiNotYetSupported() {
+
+		CriteriaBuilder builder = em.getCriteriaBuilder();
+		CriteriaQuery<User> query = builder.createQuery(User.class);
+		Root<User> root = query.from(User.class);
+		Join<User, User> join = root.join("manager", JoinType.LEFT);
+
+		Sort sort = Sort.by(Sort.Order.desc("manager").nullsFirst());
+
+		assertThatExceptionOfType(UnsupportedOperationException.class)
+				.isThrownBy(() -> QueryUtils.toOrders(sort, join, builder));
+	}
+
 	/**
 	 * This test documents an ambiguity in the JPA spec (or it's implementation in Hibernate vs EclipseLink) that we have
 	 * to work around in the test {@link #doesNotCreateJoinForOptionalAssociationWithoutFurtherNavigation()}. See also: