Polish contribution

Closes gh-6649

Author: snicoll

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/session/SessionProperties.java

@@ -144,16 +144,21 @@ public Initializer getInitializer() {
 		public class Initializer {
 
 			/**
-			 * Create the required session tables on startup if necessary.
+			 * Create the required session tables on startup if necessary. Enabled
+			 * automatically if the default table name is set or a custom schema is
+			 * configured.
 			 */
-			private boolean enabled = true;
+			private Boolean enabled;
 
 			public boolean isEnabled() {
-				boolean isDefaultTableName = DEFAULT_TABLE_NAME.equals(
+				if (this.enabled != null) {
+					return this.enabled;
+				}
+				boolean defaultTableName = DEFAULT_TABLE_NAME.equals(
 						Jdbc.this.getTableName());
-				boolean isDefaultSchema = DEFAULT_SCHEMA_LOCATION.equals(
+				boolean customSchema = !DEFAULT_SCHEMA_LOCATION.equals(
 						Jdbc.this.getSchema());
-				return this.enabled && (isDefaultTableName || !isDefaultSchema);
+				return (defaultTableName || customSchema);
 			}
 
 			public void setEnabled(boolean enabled) {

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -369,7 +369,7 @@ content into your application; rather pick only the properties that you need.
 
 	# SPRING SESSION ({sc-spring-boot-autoconfigure}/session/SessionProperties.{sc-ext}[SessionProperties])
 	spring.session.hazelcast.map-name=spring:session:sessions # Name of the map used to store sessions.
-	spring.session.jdbc.initializer.enabled=true # Create the required session tables on startup if necessary.
+	spring.session.jdbc.initializer.enabled= # Create the required session tables on startup if necessary. Enabled automatically if the default table name is set or a custom schema is configured.
 	spring.session.jdbc.schema=classpath:org/springframework/session/jdbc/schema-@@platform@@.sql # Path to the SQL file to use to initialize the database schema.
 	spring.session.jdbc.table-name=SPRING_SESSION # Name of database table used to store sessions.
 	spring.session.mongo.collection-name=sessions # Collection name used to store sessions.