Don't attempt to set null values

Update `DataSourceBuilder` so that setters are not longer called for
`null` values. This restores Spring Boot 2.4 behavior.

Fixes gh-26633

Co-authored-by: Phillip Webb <pwebb@vmware.com>

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/jdbc/DataSourceBuilder.java

@@ -176,8 +176,10 @@ public final class DataSourceBuilder<T extends DataSource> {
 		for (DataSourceProperty property : DataSourceProperty.values()) {
 			if (this.values.containsKey(property)) {
 				String value = this.values.get(property);
-				properties.set(dataSource, property, value);
-				applied.add(property);
+				if (value != null) {
+					properties.set(dataSource, property, value);
+					applied.add(property);
+				}
 			}
 			else if (deriveFromProperties != null && properties.canSet(property)) {
 				String value = deriveFromProperties.get(this.deriveFrom, property);

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/jdbc/DataSourceBuilderTests.java

@@ -73,6 +73,14 @@ class DataSourceBuilderTests {
 		assertThat(hikariDataSource.getJdbcUrl()).isEqualTo("jdbc:h2:test");
 	}
 
+	@Test // gh-26633
+	void buildWhenHikariDataSourceWithNullPasswordReturnsHikariDataSource() {
+		this.dataSource = DataSourceBuilder.create().url("jdbc:h2:test").username("test").password(null).build();
+		assertThat(this.dataSource).isInstanceOf(HikariDataSource.class);
+		HikariDataSource hikariDataSource = (HikariDataSource) this.dataSource;
+		assertThat(hikariDataSource.getJdbcUrl()).isEqualTo("jdbc:h2:test");
+	}
+
 	@Test
 	void buildWhenHikariNotAvailableReturnsTomcatDataSource() {
 		this.dataSource = DataSourceBuilder.create(new HidePackagesClassLoader("com.zaxxer.hikari")).url("jdbc:h2:test")
@@ -80,6 +88,13 @@ class DataSourceBuilderTests {
 		assertThat(this.dataSource).isInstanceOf(org.apache.tomcat.jdbc.pool.DataSource.class);
 	}
 
+	@Test // gh-26633
+	void buildWhenTomcatDataSourceWithNullPasswordReturnsDataSource() {
+		this.dataSource = DataSourceBuilder.create(new HidePackagesClassLoader("com.zaxxer.hikari")).url("jdbc:h2:test")
+				.username("test").password(null).build();
+		assertThat(this.dataSource).isInstanceOf(org.apache.tomcat.jdbc.pool.DataSource.class);
+	}
+
 	@Test
 	void buildWhenHikariAndTomcatNotAvailableReturnsDbcp2DataSource() {
 		this.dataSource = DataSourceBuilder
@@ -88,6 +103,14 @@ class DataSourceBuilderTests {
 		assertThat(this.dataSource).isInstanceOf(BasicDataSource.class);
 	}
 
+	@Test // gh-26633
+	void buildWhenDbcp2DataSourceWithNullPasswordReturnsDbcp2DataSource() {
+		this.dataSource = DataSourceBuilder
+				.create(new HidePackagesClassLoader("com.zaxxer.hikari", "org.apache.tomcat.jdbc.pool"))
+				.url("jdbc:h2:test").username("test").password(null).build();
+		assertThat(this.dataSource).isInstanceOf(BasicDataSource.class);
+	}
+
 	@Test
 	void buildWhenHikariAndTomcatAndDbcpNotAvailableReturnsOracleUcpDataSource() {
 		this.dataSource = DataSourceBuilder.create(new HidePackagesClassLoader("com.zaxxer.hikari",