From d47020d868770004f6adc74e146e6c439b581391 Mon Sep 17 00:00:00 2001
From: Mark Paluch <mpaluch@vmware.com>
Date: Tue, 28 Sep 2021 10:50:16 +0200
Subject: [PATCH] Polishing.

Reformat code. Remove duplicate, lingering Javadoc. Add override annotations. Use entities instead of < and >. Reduce method/class visibility in tests.

See #1003
Original pull request: #1018.
---
 .../data/relational/core/sql/BindMarker.java  |  2 -
 .../data/relational/core/sql/Column.java      |  1 +
 .../data/relational/core/sql/Comparison.java  |  8 +--
 .../core/sql/ConstantCondition.java           | 16 +++---
 .../core/sql/DefaultSelectBuilder.java        |  3 +-
 .../data/relational/core/sql/InlineQuery.java | 17 +++---
 .../data/relational/core/sql/Select.java      |  4 +-
 .../relational/core/sql/SelectBuilder.java    |  5 +-
 .../data/relational/core/sql/Table.java       |  6 +--
 .../data/relational/core/sql/TableLike.java   | 12 ++++-
 .../core/sql/render/ColumnVisitor.java        |  5 +-
 .../core/sql/render/ComparisonVisitor.java    |  1 -
 .../sql/render/ConstantConditionVisitor.java  |  2 +-
 .../core/sql/render/ExpressionVisitor.java    |  2 +
 .../core/sql/render/FromTableVisitor.java     |  6 +--
 .../core/sql/render/SelectListVisitor.java    |  6 ++-
 .../core/sql/render/SelectRenderContext.java  |  3 +-
 .../core/sql/render/SimpleRenderContext.java  |  4 +-
 .../render/FromClauseVisitorUnitTests.java    | 17 +++---
 .../sql/render/JoinVisitorTestsUnitTest.java  | 20 ++++---
 .../sql/render/SelectRendererUnitTests.java   | 54 +++++++++----------
 .../render/TypedSubtreeVisitorUnitTests.java  | 48 ++++++++---------
 22 files changed, 128 insertions(+), 114 deletions(-)

diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/BindMarker.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/BindMarker.java
index 16f3b65e..2a550196 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/BindMarker.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/BindMarker.java
@@ -15,8 +15,6 @@
  */
 package org.springframework.data.relational.core.sql;
 
-import org.springframework.lang.Nullable;
-
 /**
  * Bind marker/parameter placeholder used to construct prepared statements with parameter substitution.
  *
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Column.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Column.java
index 29ce325d..71f3ab2d 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Column.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Column.java
@@ -56,6 +56,7 @@ public class Column extends AbstractSegment implements Expression, Named {
 	 * @param name column name, must not {@literal null} or empty.
 	 * @param table the table, must not be {@literal null}.
 	 * @return the new {@link Column}.
+	 * @since 2.3
 	 */
 	public static Column create(String name, TableLike table) {
 
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Comparison.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Comparison.java
index 60b9e875..c04ecb49 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Comparison.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Comparison.java
@@ -61,11 +61,13 @@ public class Comparison extends AbstractSegment implements Condition {
 
 	/**
 	 * Creates a new {@link Comparison} from simple {@literal StringP} arguments
-	 * @param unqualifiedColumnName gets turned in a {@link Expressions#just(String)} and is expected to be an unqualified unique column name but also could be an verbatim expression. Must not be {@literal null}.
+	 *
+	 * @param unqualifiedColumnName gets turned in a {@link Expressions#just(String)} and is expected to be an unqualified
+	 *          unique column name but also could be an verbatim expression. Must not be {@literal null}.
 	 * @param comparator must not be {@literal null}.
 	 * @param rightValue is considered a {@link Literal}. Must not be {@literal null}.
-	 * @return a new {@literal Comparison} of the first with the third argument using the second argument as comparison operator. Guaranteed to be not {@literal null}.
-	 *
+	 * @return a new {@literal Comparison} of the first with the third argument using the second argument as comparison
+	 *         operator. Guaranteed to be not {@literal null}.
 	 * @since 2.3
 	 */
 	public static Comparison create(String unqualifiedColumnName, String comparator, Object rightValue) {
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/ConstantCondition.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/ConstantCondition.java
index f11e7036..f8f1baf3 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/ConstantCondition.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/ConstantCondition.java
@@ -23,14 +23,14 @@ package org.springframework.data.relational.core.sql;
  */
 public class ConstantCondition extends AbstractSegment implements Condition {
 
-    private final String condition;
+	private final String condition;
 
-    ConstantCondition(String condition) {
-        this.condition = condition;
-    }
+	ConstantCondition(String condition) {
+		this.condition = condition;
+	}
 
-    @Override
-    public String toString() {
-        return condition;
-    }
+	@Override
+	public String toString() {
+		return condition;
+	}
 }
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/DefaultSelectBuilder.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/DefaultSelectBuilder.java
index 1e071744..49ff3a2a 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/DefaultSelectBuilder.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/DefaultSelectBuilder.java
@@ -285,7 +285,8 @@ class DefaultSelectBuilder implements SelectBuilder, SelectAndFrom, SelectFromAn
 	@Override
 	public Select build() {
 
-		DefaultSelect select = new DefaultSelect(distinct, selectList, from, limit, offset, joins, where, orderBy, lockMode);
+		DefaultSelect select = new DefaultSelect(distinct, selectList, from, limit, offset, joins, where, orderBy,
+				lockMode);
 		SelectValidator.validate(select);
 		return select;
 	}
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/InlineQuery.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/InlineQuery.java
index 88c083af..02b3354a 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/InlineQuery.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/InlineQuery.java
@@ -18,14 +18,14 @@ package org.springframework.data.relational.core.sql;
 import org.springframework.util.Assert;
 
 /**
- * Represents a inline query within a SQL statement. Typically used in {@code FROM} or {@code JOIN} clauses.
- * <p/>
- * Renders to: {@code (<SELECT>) AS <ALIAS>} in a from or join clause, and to {@code <ALIAS>} when used in an
- * expression.
- * <p/>
+ * Represents a inline query within a SQL statement. Typically, used in {@code FROM} or {@code JOIN} clauses.
+ * <p>
+ * Renders to: {@code (&gt;SELECT&lt;) AS &gt;ALIAS&lt;} in a from or join clause, and to {@code &gt;ALIAS&lt;} when
+ * used in an expression.
+ * <p>
  * Note that this does not implement {@link Aliased} because the Alias is not optional but required and therefore more
  * like a name although the SQL term is "alias".
- * 
+ *
  * @author Jens Schauder
  * @since 2.3
  */
@@ -68,13 +68,11 @@ public class InlineQuery extends AbstractSegment implements TableLike {
 		return create(select, SqlIdentifier.unquoted(alias));
 	}
 
-	/**
-	 * @return the table name.
-	 */
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.relational.core.sql.Named#getName()
 	 */
+	@Override
 	public SqlIdentifier getName() {
 		return alias;
 	}
@@ -83,6 +81,7 @@ public class InlineQuery extends AbstractSegment implements TableLike {
 	 * @return the table name as it is used in references. This can be the actual {@link #getName() name} or an
 	 *         {@link Aliased#getAlias() alias}.
 	 */
+	@Override
 	public SqlIdentifier getReferenceName() {
 		return alias;
 	}
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Select.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Select.java
index 260e401c..73817bbf 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Select.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Select.java
@@ -15,11 +15,11 @@
  */
 package org.springframework.data.relational.core.sql;
 
-import org.springframework.lang.Nullable;
-
 import java.util.List;
 import java.util.OptionalLong;
 
+import org.springframework.lang.Nullable;
+
 /**
  * AST for a {@code SELECT} statement. Visiting order:
  * <ol>
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/SelectBuilder.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/SelectBuilder.java
index 9570d7fa..edb7b8fb 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/SelectBuilder.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/SelectBuilder.java
@@ -251,7 +251,7 @@ public interface SelectBuilder {
 	 * Builder exposing {@code FROM}, {@code JOIN}, {@code WHERE}, {@code LIMIT/OFFSET} and {@code LOCK} methods.
 	 */
 	interface SelectFromAndJoin
-		extends SelectFromAndOrderBy, BuildSelect, SelectJoin, SelectWhere, SelectLimitOffset, SelectLock {
+			extends SelectFromAndOrderBy, BuildSelect, SelectJoin, SelectWhere, SelectLimitOffset, SelectLock {
 
 		/**
 		 * Declare a {@link Table} to {@code SELECT … FROM}. Multiple calls to this or other {@code from} methods keep
@@ -317,7 +317,8 @@ public interface SelectBuilder {
 	}
 
 	/**
-	 * Builder exposing {@code FROM}, {@code WHERE}, {@code LIMIT/OFFSET}, JOIN {@code AND} and {@code LOCK} continuation methods.
+	 * Builder exposing {@code FROM}, {@code WHERE}, {@code LIMIT/OFFSET}, JOIN {@code AND} and {@code LOCK} continuation
+	 * methods.
 	 */
 	interface SelectFromAndJoinCondition
 			extends BuildSelect, SelectJoin, SelectWhere, SelectOnCondition, SelectLimitOffset, SelectLock {
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Table.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Table.java
index 64006679..39b28928 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Table.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/Table.java
@@ -107,13 +107,12 @@ public class Table extends AbstractSegment implements TableLike {
 		return new AliasedTable(name, alias);
 	}
 
-	/**
-	 * @return the table name.
-	 */
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.relational.core.sql.Named#getName()
 	 */
+	@Override
 	public SqlIdentifier getName() {
 		return name;
 	}
@@ -122,6 +121,7 @@ public class Table extends AbstractSegment implements TableLike {
 	 * @return the table name as it is used in references. This can be the actual {@link #getName() name} or an
 	 *         {@link Aliased#getAlias() alias}.
 	 */
+	@Override
 	public SqlIdentifier getReferenceName() {
 		return name;
 	}
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/TableLike.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/TableLike.java
index ef5484e5..46491dbe 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/TableLike.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/TableLike.java
@@ -15,13 +15,13 @@
  */
 package org.springframework.data.relational.core.sql;
 
-import org.springframework.util.Assert;
-
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 
+import org.springframework.util.Assert;
+
 /**
  * A segment that can be used as table in a query.
  *
@@ -61,6 +61,7 @@ public interface TableLike extends Segment {
 
 		return new Column(name, this);
 	}
+
 	/**
 	 * Creates a {@link List} of {@link Column}s associated with this {@link Table}.
 	 * <p/>
@@ -132,7 +133,14 @@ public interface TableLike extends Segment {
 		return new AsteriskFromTable(this);
 	}
 
+	/**
+	 * @return the table name.
+	 */
 	SqlIdentifier getName();
 
+	/**
+	 * @return the table name as it is used in references. This can be the actual {@link #getName() name} or an
+	 *         {@link Aliased#getAlias() alias}.
+	 */
 	SqlIdentifier getReferenceName();
 }
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ColumnVisitor.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ColumnVisitor.java
index 9f49d5e2..99ff7fed 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ColumnVisitor.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ColumnVisitor.java
@@ -22,9 +22,8 @@ import org.springframework.data.relational.core.sql.Visitable;
 import org.springframework.lang.Nullable;
 
 /**
- * Renderer for {@link Column}s. Renders a column as {@literal 
- * <table>
- * .<column>} or {@literal <column>}.
+ * Renderer for {@link Column}s. Renders a column as {@literal &gt;table&lt;.&gt;column&lt;} or
+ * {@literal &gt;column&lt;}.
  *
  * @author Mark Paluch
  * @since 1.1
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ComparisonVisitor.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ComparisonVisitor.java
index d9c1cb94..186c0601 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ComparisonVisitor.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ComparisonVisitor.java
@@ -18,7 +18,6 @@ package org.springframework.data.relational.core.sql.render;
 import org.springframework.data.relational.core.sql.Comparison;
 import org.springframework.data.relational.core.sql.Condition;
 import org.springframework.data.relational.core.sql.Expression;
-import org.springframework.data.relational.core.sql.SimpleFunction;
 import org.springframework.data.relational.core.sql.Visitable;
 import org.springframework.lang.Nullable;
 
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ConstantConditionVisitor.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ConstantConditionVisitor.java
index 5afd1bf1..09df0a65 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ConstantConditionVisitor.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ConstantConditionVisitor.java
@@ -33,8 +33,8 @@ class ConstantConditionVisitor extends TypedSingleConditionRenderSupport<Constan
 	}
 
 	/**
-	 *
 	 * (non-Javadoc)
+	 *
 	 * @see org.springframework.data.relational.core.sql.render.TypedSubtreeVisitor#leaveMatched(org.springframework.data.relational.core.sql.Visitable)
 	 */
 	@Override
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ExpressionVisitor.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ExpressionVisitor.java
index 0f890f29..43f391c9 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ExpressionVisitor.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/ExpressionVisitor.java
@@ -46,6 +46,7 @@ class ExpressionVisitor extends TypedSubtreeVisitor<Expression> implements PartR
 
 	/**
 	 * Creates an {@code ExpressionVisitor} that does not use aliases for column names
+	 *
 	 * @param context must not be {@literal null}.
 	 */
 	ExpressionVisitor(RenderContext context) {
@@ -155,6 +156,7 @@ class ExpressionVisitor extends TypedSubtreeVisitor<Expression> implements PartR
 
 	/**
 	 * Describes how aliases of columns should be rendered.
+	 *
 	 * @since 2.3
 	 */
 	enum AliasHandling {
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/FromTableVisitor.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/FromTableVisitor.java
index 89bffd35..a8f2e333 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/FromTableVisitor.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/FromTableVisitor.java
@@ -35,10 +35,8 @@ class FromTableVisitor extends TypedSubtreeVisitor<TableLike> {
 
 	private final RenderContext context;
 	private final RenderTarget parent;
-	@Nullable
-	private SelectStatementVisitor delegate;
-	@Nullable
-	private StringBuilder builder = null;
+	@Nullable private SelectStatementVisitor delegate;
+	@Nullable private StringBuilder builder = null;
 
 	FromTableVisitor(RenderContext context, RenderTarget parent) {
 		super();
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SelectListVisitor.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SelectListVisitor.java
index 8c4fd8c8..bea45006 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SelectListVisitor.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SelectListVisitor.java
@@ -15,7 +15,10 @@
  */
 package org.springframework.data.relational.core.sql.render;
 
-import org.springframework.data.relational.core.sql.*;
+import org.springframework.data.relational.core.sql.Aliased;
+import org.springframework.data.relational.core.sql.Expression;
+import org.springframework.data.relational.core.sql.SelectList;
+import org.springframework.data.relational.core.sql.Visitable;
 
 /**
  * {@link PartRenderer} for {@link SelectList}s.
@@ -99,5 +102,4 @@ class SelectListVisitor extends TypedSubtreeVisitor<SelectList> implements PartR
 		return builder;
 	}
 
-
 }
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SelectRenderContext.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SelectRenderContext.java
index faa9d199..b420fefe 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SelectRenderContext.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SelectRenderContext.java
@@ -41,8 +41,7 @@ public interface SelectRenderContext {
 	}
 
 	/**
-	 * Customization hook: Rendition of a part after {@code FROM} table.
-	 * Renders an empty string by default.
+	 * Customization hook: Rendition of a part after {@code FROM} table. Renders an empty string by default.
 	 *
 	 * @return render {@link Function} invoked after rendering {@code FROM} table.
 	 */
diff --git a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SimpleRenderContext.java b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SimpleRenderContext.java
index 7ba11068..9f4d942f 100644
--- a/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SimpleRenderContext.java
+++ b/spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SimpleRenderContext.java
@@ -48,9 +48,7 @@ final class SimpleRenderContext implements RenderContext {
 	@Override
 	public String toString() {
 
-		return "SimpleRenderContext{" +
-				"namingStrategy=" + namingStrategy +
-				'}';
+		return "SimpleRenderContext{" + "namingStrategy=" + namingStrategy + '}';
 	}
 
 	enum DefaultSelectRenderContext implements SelectRenderContext {
diff --git a/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/FromClauseVisitorUnitTests.java b/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/FromClauseVisitorUnitTests.java
index a0cb0d1d..389b77c1 100644
--- a/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/FromClauseVisitorUnitTests.java
+++ b/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/FromClauseVisitorUnitTests.java
@@ -15,13 +15,14 @@
  */
 package org.springframework.data.relational.core.sql.render;
 
-import static java.util.Arrays.*;
 import static org.assertj.core.api.Assertions.*;
 
+import java.util.Arrays;
 import java.util.List;
 
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
+
 import org.springframework.data.relational.core.sql.Column;
 import org.springframework.data.relational.core.sql.From;
 import org.springframework.data.relational.core.sql.InlineQuery;
@@ -34,7 +35,7 @@ import org.springframework.data.relational.core.sql.TestFrom;
  *
  * @author Jens Schauder
  */
-public class FromClauseVisitorUnitTests {
+class FromClauseVisitorUnitTests {
 
 	StringBuilder renderResult = new StringBuilder();
 	FromClauseVisitor visitor = new FromClauseVisitor(new SimpleRenderContext(NamingStrategies.asIs()), renderResult::append);
@@ -47,17 +48,17 @@ public class FromClauseVisitorUnitTests {
 
 		from.visit(visitor);
 
-		assertThat(renderResult.toString()).isEqualTo(f.renderResult);
+		assertThat(renderResult).hasToString(f.renderResult);
 	}
 
 	static List<Fixture> testRendering() {
 
-		final Table tabOne = Table.create("tabOne");
-		final Table tabTwo = Table.create("tabTwo");
-		final Select selectOne = Select.builder().select(Column.create("oneId", tabOne)).from(tabOne).build();
-		final Select selectTwo = Select.builder().select(Column.create("twoId", tabTwo)).from(tabTwo).build();
+		Table tabOne = Table.create("tabOne");
+		Table tabTwo = Table.create("tabTwo");
+		Select selectOne = Select.builder().select(Column.create("oneId", tabOne)).from(tabOne).build();
+		Select selectTwo = Select.builder().select(Column.create("twoId", tabTwo)).from(tabTwo).build();
 
-		return asList(
+		return Arrays.asList(
 				fixture("single table", new TestFrom(Table.create("one")), "one"),
 				fixture("single table with alias", new TestFrom(Table.aliased("one", "one_alias")), "one one_alias"),
 				fixture("multiple tables", new TestFrom(Table.create("one"),Table.create("two")), "one, two"),
diff --git a/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/JoinVisitorTestsUnitTest.java b/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/JoinVisitorTestsUnitTest.java
index 382608ea..bec6b8f8 100644
--- a/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/JoinVisitorTestsUnitTest.java
+++ b/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/JoinVisitorTestsUnitTest.java
@@ -15,13 +15,14 @@
  */
 package org.springframework.data.relational.core.sql.render;
 
-import static java.util.Arrays.*;
 import static org.assertj.core.api.Assertions.*;
 
+import java.util.Arrays;
 import java.util.List;
 
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
+
 import org.springframework.data.relational.core.sql.Column;
 import org.springframework.data.relational.core.sql.InlineQuery;
 import org.springframework.data.relational.core.sql.Join;
@@ -30,6 +31,11 @@ import org.springframework.data.relational.core.sql.Table;
 import org.springframework.data.relational.core.sql.TestJoin;
 import org.springframework.data.relational.core.sql.Visitor;
 
+/**
+ * Unit tests for {@link JoinVisitor}.
+ *
+ * @author Jens Schauder
+ */
 public class JoinVisitorTestsUnitTest {
 
 	final StringBuilder builder = new StringBuilder();
@@ -43,7 +49,7 @@ public class JoinVisitorTestsUnitTest {
 
 		join.visit(visitor);
 
-		assertThat(builder.toString()).isEqualTo(f.renderResult);
+		assertThat(builder).hasToString(f.renderResult);
 	}
 
 	static List<Fixture> renderJoins() {
@@ -51,11 +57,11 @@ public class JoinVisitorTestsUnitTest {
 		Column colOne = Column.create("colOne", Table.create("tabOne"));
 		Table tabTwo = Table.create("tabTwo");
 		Column colTwo = Column.create("colTwo", tabTwo);
-		final Column renamed = colOne.as("renamed");
-		final Select select = Select.builder().select(renamed).from(colOne.getTable()).build();
-		final InlineQuery inlineQuery = InlineQuery.create(select, "inline");
+		Column renamed = colOne.as("renamed");
+		Select select = Select.builder().select(renamed).from(colOne.getTable()).build();
+		InlineQuery inlineQuery = InlineQuery.create(select, "inline");
 
-		return asList(
+		return Arrays.asList(
 				fixture("simple join", new TestJoin(Join.JoinType.JOIN, tabTwo, colOne.isEqualTo(colTwo)),
 						"JOIN tabTwo ON tabOne.colOne = tabTwo.colTwo"),
 				fixture("inlineQuery",
@@ -65,7 +71,7 @@ public class JoinVisitorTestsUnitTest {
 
 	private static Fixture fixture(String comment, Join join, String renderResult) {
 
-		final Fixture fixture = new Fixture();
+		Fixture fixture = new Fixture();
 		fixture.comment = comment;
 		fixture.join = join;
 		fixture.renderResult = renderResult;
diff --git a/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/SelectRendererUnitTests.java b/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/SelectRendererUnitTests.java
index c194fbc1..0394d4ba 100644
--- a/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/SelectRendererUnitTests.java
+++ b/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/SelectRendererUnitTests.java
@@ -29,10 +29,10 @@ import org.springframework.util.StringUtils;
  * @author Mark Paluch
  * @author Jens Schauder
  */
-public class SelectRendererUnitTests {
+class SelectRendererUnitTests {
 
 	@Test // DATAJDBC-309, DATAJDBC-278
-	public void shouldRenderSingleColumn() {
+	void shouldRenderSingleColumn() {
 
 		Table bar = SQL.table("bar");
 		Column foo = bar.column("foo");
@@ -43,7 +43,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test
-	public void honorsNamingStrategy() {
+	void honorsNamingStrategy() {
 
 		Table bar = SQL.table("bar");
 		Column foo = bar.column("foo");
@@ -55,7 +55,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRenderAliasedColumnAndFrom() {
+	void shouldRenderAliasedColumnAndFrom() {
 
 		Table table = Table.create("bar").as("my_bar");
 
@@ -65,7 +65,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRenderMultipleColumnsFromTables() {
+	void shouldRenderMultipleColumnsFromTables() {
 
 		Table table1 = Table.create("table1");
 		Table table2 = Table.create("table2");
@@ -77,7 +77,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRenderDistinct() {
+	void shouldRenderDistinct() {
 
 		Table table = SQL.table("bar");
 		Column foo = table.column("foo");
@@ -89,7 +89,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRenderCountFunction() {
+	void shouldRenderCountFunction() {
 
 		Table table = SQL.table("bar");
 		Column foo = table.column("foo");
@@ -101,7 +101,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-340
-	public void shouldRenderCountFunctionWithAliasedColumn() {
+	void shouldRenderCountFunctionWithAliasedColumn() {
 
 		Table table = SQL.table("bar");
 		Column foo = table.column("foo").as("foo_bar");
@@ -112,7 +112,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRenderSimpleJoin() {
+	void shouldRenderSimpleJoin() {
 
 		Table employee = SQL.table("employee");
 		Table department = SQL.table("department");
@@ -126,7 +126,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-340
-	public void shouldRenderOuterJoin() {
+	void shouldRenderOuterJoin() {
 
 		Table employee = SQL.table("employee");
 		Table department = SQL.table("department");
@@ -141,7 +141,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRenderSimpleJoinWithAnd() {
+	void shouldRenderSimpleJoinWithAnd() {
 
 		Table employee = SQL.table("employee");
 		Table department = SQL.table("department");
@@ -157,7 +157,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRenderMultipleJoinWithAnd() {
+	void shouldRenderMultipleJoinWithAnd() {
 
 		Table employee = SQL.table("employee");
 		Table department = SQL.table("department");
@@ -176,7 +176,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // GH-1003
-	public void shouldRenderJoinWithInlineQuery() {
+	void shouldRenderJoinWithInlineQuery() {
 
 		Table employee = SQL.table("employee");
 		Table department = SQL.table("department");
@@ -199,7 +199,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // GH-1003
-	public void shouldRenderJoinWithTwoInlineQueries() {
+	void shouldRenderJoinWithTwoInlineQueries() {
 
 		Table employee = SQL.table("employee");
 		Table department = SQL.table("department");
@@ -225,7 +225,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRenderOrderByName() {
+	void shouldRenderOrderByName() {
 
 		Table employee = SQL.table("employee").as("emp");
 		Column column = employee.column("name").as("emp_name");
@@ -237,7 +237,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRenderIsNull() {
+	void shouldRenderIsNull() {
 
 		Table table = SQL.table("foo");
 		Column bar = table.column("bar");
@@ -248,7 +248,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRenderNotNull() {
+	void shouldRenderNotNull() {
 
 		Table table = SQL.table("foo");
 		Column bar = table.column("bar");
@@ -259,7 +259,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRenderEqualityCondition() {
+	void shouldRenderEqualityCondition() {
 
 		Table table = SQL.table("foo");
 		Column bar = table.column("bar");
@@ -271,7 +271,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRendersAndOrConditionWithProperParentheses() {
+	void shouldRendersAndOrConditionWithProperParentheses() {
 
 		Table table = SQL.table("foo");
 		Column bar = table.column("bar");
@@ -285,7 +285,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldInWithNamedParameter() {
+	void shouldInWithNamedParameter() {
 
 		Table table = SQL.table("foo");
 		Column bar = table.column("bar");
@@ -296,7 +296,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldInWithNamedParameters() {
+	void shouldInWithNamedParameters() {
 
 		Table table = SQL.table("foo");
 		Column bar = table.column("bar");
@@ -308,7 +308,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldRenderInSubselect() {
+	void shouldRenderInSubselect() {
 
 		Table foo = SQL.table("foo");
 		Column bar = foo.column("bar");
@@ -325,7 +325,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-309
-	public void shouldConsiderNamingStrategy() {
+	void shouldConsiderNamingStrategy() {
 
 		Table foo = SQL.table("Foo");
 		Column bar = foo.column("BaR");
@@ -345,7 +345,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-340
-	public void shouldRenderCountStar() {
+	void shouldRenderCountStar() {
 
 		Select select = Select.builder() //
 				.select(Functions.count(Expressions.asterisk())) //
@@ -358,7 +358,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-340
-	public void shouldRenderCountTableStar() {
+	void shouldRenderCountTableStar() {
 
 		Table foo = SQL.table("foo");
 		Select select = Select.builder() //
@@ -372,7 +372,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-340
-	public void shouldRenderFunctionWithAlias() {
+	void shouldRenderFunctionWithAlias() {
 
 		Table foo = SQL.table("foo");
 		Select select = Select.builder() //
@@ -386,7 +386,7 @@ public class SelectRendererUnitTests {
 	}
 
 	@Test // DATAJDBC-479
-	public void shouldRenderWithRenderContext() {
+	void shouldRenderWithRenderContext() {
 
 		Table table = Table.create(SqlIdentifier.quoted("my_table"));
 		Table join_table = Table.create(SqlIdentifier.quoted("join_table"));
diff --git a/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/TypedSubtreeVisitorUnitTests.java b/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/TypedSubtreeVisitorUnitTests.java
index d20dc2a2..45beeb95 100644
--- a/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/TypedSubtreeVisitorUnitTests.java
+++ b/spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/TypedSubtreeVisitorUnitTests.java
@@ -29,7 +29,7 @@ import org.springframework.data.relational.core.sql.Visitable;
 
 /**
  * Unit tests for {@link org.springframework.data.relational.core.sql.render.TypedSubtreeVisitor}.
- * 
+ *
  * @author Jens Schauder
  */
 class TypedSubtreeVisitorUnitTests {
@@ -39,8 +39,8 @@ class TypedSubtreeVisitorUnitTests {
 	@Test // GH-1003
 	void enterAndLeavesSingleSegment() {
 
-		final TypedSubtreeVisitor<TestSegment> visitor = new LoggingTypedSubtreeVisitor();
-		final TestSegment root = new TestSegment("root");
+		TypedSubtreeVisitor<TestSegment> visitor = new LoggingTypedSubtreeVisitor();
+		TestSegment root = new TestSegment("root");
 
 		root.visit(visitor);
 
@@ -50,8 +50,8 @@ class TypedSubtreeVisitorUnitTests {
 	@Test // GH-1003
 	void enterAndLeavesChainOfMatchingSegmentsAsNested() {
 
-		final TypedSubtreeVisitor<TestSegment> visitor = new LoggingTypedSubtreeVisitor();
-		final TestSegment root = new TestSegment("root", new TestSegment("level 1", new TestSegment("level 2")));
+		TypedSubtreeVisitor<TestSegment> visitor = new LoggingTypedSubtreeVisitor();
+		TestSegment root = new TestSegment("root", new TestSegment("level 1", new TestSegment("level 2")));
 
 		root.visit(visitor);
 
@@ -62,8 +62,8 @@ class TypedSubtreeVisitorUnitTests {
 	@Test // GH-1003
 	void enterAndLeavesMatchingChildrenAsNested() {
 
-		final TypedSubtreeVisitor<TestSegment> visitor = new LoggingTypedSubtreeVisitor();
-		final TestSegment root = new TestSegment("root", new TestSegment("child 1"), new TestSegment("child 2"));
+		TypedSubtreeVisitor<TestSegment> visitor = new LoggingTypedSubtreeVisitor();
+		TestSegment root = new TestSegment("root", new TestSegment("child 1"), new TestSegment("child 2"));
 
 		root.visit(visitor);
 
@@ -74,8 +74,8 @@ class TypedSubtreeVisitorUnitTests {
 	@Test // GH-1003
 	void enterAndLeavesChainOfOtherSegmentsAsNested() {
 
-		final TypedSubtreeVisitor<TestSegment> visitor = new LoggingTypedSubtreeVisitor();
-		final TestSegment root = new TestSegment("root", new OtherSegment("level 1", new OtherSegment("level 2")));
+		TypedSubtreeVisitor<TestSegment> visitor = new LoggingTypedSubtreeVisitor();
+		TestSegment root = new TestSegment("root", new OtherSegment("level 1", new OtherSegment("level 2")));
 
 		root.visit(visitor);
 
@@ -86,8 +86,8 @@ class TypedSubtreeVisitorUnitTests {
 	@Test // GH-1003
 	void enterAndLeavesOtherChildrenAsNested() {
 
-		final TypedSubtreeVisitor<TestSegment> visitor = new LoggingTypedSubtreeVisitor();
-		final TestSegment root = new TestSegment("root", new OtherSegment("child 1"), new OtherSegment("child 2"));
+		TypedSubtreeVisitor<TestSegment> visitor = new LoggingTypedSubtreeVisitor();
+		TestSegment root = new TestSegment("root", new OtherSegment("child 1"), new OtherSegment("child 2"));
 
 		root.visit(visitor);
 
@@ -98,9 +98,9 @@ class TypedSubtreeVisitorUnitTests {
 	@Test // GH-1003
 	void visitorIsReentrant() {
 
-		final LoggingTypedSubtreeVisitor visitor = new LoggingTypedSubtreeVisitor();
-		final TestSegment root1 = new TestSegment("root 1");
-		final TestSegment root2 = new TestSegment("root 2");
+		LoggingTypedSubtreeVisitor visitor = new LoggingTypedSubtreeVisitor();
+		TestSegment root1 = new TestSegment("root 1");
+		TestSegment root2 = new TestSegment("root 2");
 
 		root1.visit(visitor);
 		root2.visit(visitor);
@@ -112,10 +112,10 @@ class TypedSubtreeVisitorUnitTests {
 	@Test // GH-1003
 	void delegateToOtherVisitorOnEnterMatchedRevisitsTheSegment() {
 
-		final LoggingTypedSubtreeVisitor first = new LoggingTypedSubtreeVisitor("first ");
-		final LoggingTypedSubtreeVisitor second = new LoggingTypedSubtreeVisitor("second ");
+		LoggingTypedSubtreeVisitor first = new LoggingTypedSubtreeVisitor("first ");
+		LoggingTypedSubtreeVisitor second = new LoggingTypedSubtreeVisitor("second ");
 		first.enterMatched(s -> delegateTo(second));
-		final TestSegment root = new TestSegment("root", new TestSegment("child 1"), new TestSegment("child 2"));
+		TestSegment root = new TestSegment("root", new TestSegment("child 1"), new TestSegment("child 2"));
 
 		root.visit(first);
 
@@ -127,11 +127,11 @@ class TypedSubtreeVisitorUnitTests {
 	@Test // GH-1003
 	void delegateToOtherVisitorOnEnterNestedRevisitsTheNestedSegment() {
 
-		final LoggingTypedSubtreeVisitor first = new LoggingTypedSubtreeVisitor("first ");
-		final LoggingTypedSubtreeVisitor second = new LoggingTypedSubtreeVisitor("second ");
+		LoggingTypedSubtreeVisitor first = new LoggingTypedSubtreeVisitor("first ");
+		LoggingTypedSubtreeVisitor second = new LoggingTypedSubtreeVisitor("second ");
 		first.enterNested(
 				s -> ((TestSegment) s).name.equals("child 2") ? delegateTo(second) : DelegatingVisitor.Delegation.retain());
-		final TestSegment root = new TestSegment("root", new TestSegment("child 1"), new TestSegment("child 2"),
+		TestSegment root = new TestSegment("root", new TestSegment("child 1"), new TestSegment("child 2"),
 				new TestSegment("child 3"));
 
 		root.visit(first);
@@ -144,7 +144,7 @@ class TypedSubtreeVisitorUnitTests {
 
 	static class TestSegment extends AbstractTestSegment {
 
-		private final String name;
+		private String name;
 
 		TestSegment(String name, Segment... children) {
 
@@ -160,7 +160,7 @@ class TypedSubtreeVisitorUnitTests {
 
 	static class OtherSegment extends AbstractTestSegment {
 
-		private final String name;
+		private String name;
 
 		public OtherSegment(String name, Segment... children) {
 
@@ -176,7 +176,7 @@ class TypedSubtreeVisitorUnitTests {
 
 	class LoggingTypedSubtreeVisitor extends TypedSubtreeVisitor<TestSegment> {
 
-		final String prefix;
+		String prefix;
 		Function<TestSegment, Delegation> enterMatchedDelegation;
 		Function<Visitable, Delegation> enterNestedDelegation;
 
@@ -192,7 +192,7 @@ class TypedSubtreeVisitorUnitTests {
 		Delegation enterMatched(TestSegment segment) {
 
 			events.add(prefix + "enter matched " + segment);
-			final Delegation delegation = super.enterMatched(segment);
+			Delegation delegation = super.enterMatched(segment);
 
 			return enterMatchedDelegation == null ? delegation : enterMatchedDelegation.apply(segment);
 		}