diff --git a/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/Credentials.java b/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/Credentials.java
index 673adad41b..e51937cf57 100644
--- a/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/Credentials.java
+++ b/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/Credentials.java
@@ -2,27 +2,27 @@ package com.baeldung.boot.configurationproperties;
 
 public class Credentials {
 
-	private String username;
-	private String password;
+    private String username;
+    private String password;
 
-	public Credentials(String username, String password) {
-		this.username = username;
-		this.password = password;
-	}
+    public Credentials(String username, String password) {
+        this.username = username;
+        this.password = password;
+    }
 
-	public String getUsername() {
-		return username;
-	}
+    public String getUsername() {
+        return username;
+    }
 
-	public void setUsername(String username) {
-		this.username = username;
-	}
+    public void setUsername(String username) {
+        this.username = username;
+    }
 
-	public String getPassword() {
-		return password;
-	}
+    public String getPassword() {
+        return password;
+    }
 
-	public void setPassword(String password) {
-		this.password = password;
-	}
+    public void setPassword(String password) {
+        this.password = password;
+    }
 }
diff --git a/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/CustomCredentialsConverter.java b/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/CustomCredentialsConverter.java
index deb71dcdad..ef160c8c9a 100644
--- a/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/CustomCredentialsConverter.java
+++ b/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/CustomCredentialsConverter.java
@@ -8,9 +8,9 @@ import org.springframework.stereotype.Component;
 @ConfigurationPropertiesBinding
 public class CustomCredentialsConverter implements Converter<String, Credentials> {
 
-	@Override
-	public Credentials convert(String source) {
-		String data[] = source.split(",");
-		return new Credentials(data[0], data[1]);
-	}
+    @Override
+    public Credentials convert(String source) {
+        String[] data = source.split(",");
+        return new Credentials(data[0], data[1]);
+    }
 }
diff --git a/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/MailServer.java b/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/MailServer.java
index 8ba42d76f8..e23b30759b 100644
--- a/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/MailServer.java
+++ b/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/MailServer.java
@@ -19,41 +19,41 @@ import org.springframework.validation.annotation.Validated;
 @Validated
 public class MailServer {
 
-	@NotNull
-	@NotEmpty
-	private Map<String, @NotBlank String> propertiesMap;
+    @NotNull
+    @NotEmpty
+    private Map<String, @NotBlank String> propertiesMap;
 
-	@Valid
-	private MailConfig mailConfig = new MailConfig();
+    @Valid
+    private MailConfig mailConfig = new MailConfig();
 
-	public static class MailConfig {
+    public static class MailConfig {
 
-		@NotBlank
-		@Email
-		private String address;
+        @NotBlank
+        @Email
+        private String address;
 
-		public String getAddress() {
-			return address;
-		}
+        public String getAddress() {
+            return address;
+        }
 
-		public void setAddress(String address) {
-			this.address = address;
-		}
-	}
+        public void setAddress(String address) {
+            this.address = address;
+        }
+    }
 
-	public Map<String, String> getPropertiesMap() {
-		return propertiesMap;
-	}
+    public Map<String, String> getPropertiesMap() {
+        return propertiesMap;
+    }
 
-	public void setPropertiesMap(Map<String, String> propertiesMap) {
-		this.propertiesMap = propertiesMap;
-	}
+    public void setPropertiesMap(Map<String, String> propertiesMap) {
+        this.propertiesMap = propertiesMap;
+    }
 
-	public MailConfig getMailConfig() {
-		return mailConfig;
-	}
+    public MailConfig getMailConfig() {
+        return mailConfig;
+    }
 
-	public void setMailConfig(MailConfig mailConfig) {
-		this.mailConfig = mailConfig;
-	}
+    public void setMailConfig(MailConfig mailConfig) {
+        this.mailConfig = mailConfig;
+    }
 }
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/PropertyConversion.java b/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/PropertyConversion.java
index 9747858ed7..9b2ea39299 100644
--- a/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/PropertyConversion.java
+++ b/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/PropertyConversion.java
@@ -13,55 +13,55 @@ import org.springframework.util.unit.DataUnit;
 @ConfigurationProperties(prefix = "server")
 public class PropertyConversion {
 
-	private DataSize uploadSpeed;
+    private DataSize uploadSpeed;
 
-	@DataSizeUnit(DataUnit.GIGABYTES)
-	private DataSize downloadSpeed;
+    @DataSizeUnit(DataUnit.GIGABYTES)
+    private DataSize downloadSpeed;
 
-	private Duration backupDay;
+    private Duration backupDay;
 
-	@DurationUnit(ChronoUnit.HOURS)
-	private Duration backupHour;
+    @DurationUnit(ChronoUnit.HOURS)
+    private Duration backupHour;
 
-	private Credentials credentials;
+    private Credentials credentials;
 
-	public Duration getBackupDay() {
-		return backupDay;
-	}
+    public Duration getBackupDay() {
+        return backupDay;
+    }
 
-	public void setBackupDay(Duration backupDay) {
-		this.backupDay = backupDay;
-	}
+    public void setBackupDay(Duration backupDay) {
+        this.backupDay = backupDay;
+    }
 
-	public Duration getBackupHour() {
-		return backupHour;
-	}
+    public Duration getBackupHour() {
+        return backupHour;
+    }
 
-	public void setBackupHour(Duration backupHour) {
-		this.backupHour = backupHour;
-	}
+    public void setBackupHour(Duration backupHour) {
+        this.backupHour = backupHour;
+    }
 
-	public DataSize getUploadSpeed() {
-		return uploadSpeed;
-	}
+    public DataSize getUploadSpeed() {
+        return uploadSpeed;
+    }
 
-	public void setUploadSpeed(DataSize uploadSpeed) {
-		this.uploadSpeed = uploadSpeed;
-	}
+    public void setUploadSpeed(DataSize uploadSpeed) {
+        this.uploadSpeed = uploadSpeed;
+    }
 
-	public DataSize getDownloadSpeed() {
-		return downloadSpeed;
-	}
+    public DataSize getDownloadSpeed() {
+        return downloadSpeed;
+    }
 
-	public void setDownloadSpeed(DataSize downloadSpeed) {
-		this.downloadSpeed = downloadSpeed;
-	}
+    public void setDownloadSpeed(DataSize downloadSpeed) {
+        this.downloadSpeed = downloadSpeed;
+    }
 
-	public Credentials getCredentials() {
-		return credentials;
-	}
+    public Credentials getCredentials() {
+        return credentials;
+    }
 
-	public void setCredentials(Credentials credentials) {
-		this.credentials = credentials;
-	}
+    public void setCredentials(Credentials credentials) {
+        this.credentials = credentials;
+    }
 }
diff --git a/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/ServerConfig.java b/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/ServerConfig.java
index bfacc6e679..0c9e62445a 100644
--- a/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/ServerConfig.java
+++ b/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/ServerConfig.java
@@ -9,35 +9,35 @@ import org.springframework.context.annotation.Configuration;
 @ConfigurationProperties(prefix = "server")
 public class ServerConfig {
 
-	private Address address;
-	private Map<String, String> resourcesPath;
+    private Address address;
+    private Map<String, String> resourcesPath;
 
-	public static class Address {
+    public static class Address {
 
-		private String ip;
+        private String ip;
 
-		public String getIp() {
-			return ip;
-		}
+        public String getIp() {
+            return ip;
+        }
 
-		public void setIp(String ip) {
-			this.ip = ip;
-		}
-	}
+        public void setIp(String ip) {
+            this.ip = ip;
+        }
+    }
 
-	public Address getAddress() {
-		return address;
-	}
+    public Address getAddress() {
+        return address;
+    }
 
-	public void setAddress(Address address) {
-		this.address = address;
-	}
+    public void setAddress(Address address) {
+        this.address = address;
+    }
 
-	public Map<String, String> getResourcesPath() {
-		return resourcesPath;
-	}
+    public Map<String, String> getResourcesPath() {
+        return resourcesPath;
+    }
 
-	public void setResourcesPath(Map<String, String> resourcesPath) {
-		this.resourcesPath = resourcesPath;
-	}
+    public void setResourcesPath(Map<String, String> resourcesPath) {
+        this.resourcesPath = resourcesPath;
+    }
 }
diff --git a/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/ServerConfigFactory.java b/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/ServerConfigFactory.java
index 8d74de1732..9d337123c7 100644
--- a/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/ServerConfigFactory.java
+++ b/spring-boot-modules/spring-boot-testing/src/main/java/com/baeldung/boot/configurationproperties/ServerConfigFactory.java
@@ -7,9 +7,9 @@ import org.springframework.context.annotation.Configuration;
 @Configuration
 public class ServerConfigFactory {
 
-	@Bean
-	@ConfigurationProperties(prefix = "server.default")
-	public ServerConfig getDefaultConfigs() {
-		return new ServerConfig();
-	}
+    @Bean
+    @ConfigurationProperties(prefix = "server.default")
+    public ServerConfig getDefaultConfigs() {
+        return new ServerConfig();
+    }
 }
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/BindingPropertiesToBeanMethodsUnitTest.java b/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/BindingPropertiesToBeanMethodsUnitTest.java
index a5bc09e290..743cb26a18 100644
--- a/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/BindingPropertiesToBeanMethodsUnitTest.java
+++ b/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/BindingPropertiesToBeanMethodsUnitTest.java
@@ -19,16 +19,18 @@ import org.springframework.test.context.junit.jupiter.SpringExtension;
 @TestPropertySource("classpath:server-config-test.properties")
 public class BindingPropertiesToBeanMethodsUnitTest {
 
-	@Autowired
-	private ServerConfigFactory configFactory;
+    @Autowired
+    private ServerConfigFactory configFactory;
 
-	@Test
-	void givenBeanAnnotatedMethod_whenBindingProperties_thenAllFieldsAreSet() {
+    @Test
+    void givenBeanAnnotatedMethod_whenBindingProperties_thenAllFieldsAreSet() {
+        assertEquals("192.168.0.2", configFactory.getDefaultConfigs()
+            .getAddress()
+            .getIp());
 
-		assertEquals("192.168.0.2", configFactory.getDefaultConfigs().getAddress().getIp());
-
-		Map<String, String> expectedResourcesPath = new HashMap<>();
-		expectedResourcesPath.put("imgs", "/root/def/imgs");
-		assertEquals(expectedResourcesPath, configFactory.getDefaultConfigs().getResourcesPath());
-	}
+        Map<String, String> expectedResourcesPath = new HashMap<>();
+        expectedResourcesPath.put("imgs", "/root/def/imgs");
+        assertEquals(expectedResourcesPath, configFactory.getDefaultConfigs()
+            .getResourcesPath());
+    }
 }
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/BindingPropertiesToUserDefinedPOJOUnitTest.java b/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/BindingPropertiesToUserDefinedPOJOUnitTest.java
index 96bbc6639a..9db906fa04 100644
--- a/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/BindingPropertiesToUserDefinedPOJOUnitTest.java
+++ b/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/BindingPropertiesToUserDefinedPOJOUnitTest.java
@@ -17,16 +17,16 @@ import org.springframework.test.context.junit.jupiter.SpringExtension;
 @TestPropertySource("classpath:server-config-test.properties")
 public class BindingPropertiesToUserDefinedPOJOUnitTest {
 
-	@Autowired
-	private ServerConfig serverConfig;
+    @Autowired
+    private ServerConfig serverConfig;
 
-	@Test
-	void givenUserDefinedPOJO_whenBindingPropertiesFile_thenAllFieldsAreSet() {
+    @Test
+    void givenUserDefinedPOJO_whenBindingPropertiesFile_thenAllFieldsAreSet() {
+        assertEquals("192.168.0.1", serverConfig.getAddress()
+            .getIp());
 
-		assertEquals("192.168.0.1", serverConfig.getAddress().getIp());
-
-		Map<String, String> expectedResourcesPath = new HashMap<>();
-		expectedResourcesPath.put("imgs", "/root/imgs");
-		assertEquals(expectedResourcesPath, serverConfig.getResourcesPath());
-	}
+        Map<String, String> expectedResourcesPath = new HashMap<>();
+        expectedResourcesPath.put("imgs", "/root/imgs");
+        assertEquals(expectedResourcesPath, serverConfig.getResourcesPath());
+    }
 }
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/BindingYMLPropertiesUnitTest.java b/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/BindingYMLPropertiesUnitTest.java
index eda8eb7f6b..5543f5e9e8 100644
--- a/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/BindingYMLPropertiesUnitTest.java
+++ b/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/BindingYMLPropertiesUnitTest.java
@@ -18,16 +18,16 @@ import org.springframework.test.context.junit.jupiter.SpringExtension;
 @ActiveProfiles("test")
 public class BindingYMLPropertiesUnitTest {
 
-	@Autowired
-	private ServerConfig serverConfig;
+    @Autowired
+    private ServerConfig serverConfig;
 
-	@Test
-	void whenBindingYMLConfigFile_thenAllFieldsAreSet() {
+    @Test
+    void whenBindingYMLConfigFile_thenAllFieldsAreSet() {
+        assertEquals("192.168.0.4", serverConfig.getAddress()
+            .getIp());
 
-		assertEquals("192.168.0.4", serverConfig.getAddress().getIp());
-
-		Map<String, String> expectedResourcesPath = new HashMap<>();
-		expectedResourcesPath.put("imgs", "/etc/test/imgs");
-		assertEquals(expectedResourcesPath, serverConfig.getResourcesPath());
-	}
+        Map<String, String> expectedResourcesPath = new HashMap<>();
+        expectedResourcesPath.put("imgs", "/etc/test/imgs");
+        assertEquals(expectedResourcesPath, serverConfig.getResourcesPath());
+    }
 }
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/OverridingConfigurationPropertiesUnitTest.java b/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/OverridingConfigurationPropertiesUnitTest.java
index 8631308296..2779b0a313 100644
--- a/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/OverridingConfigurationPropertiesUnitTest.java
+++ b/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/OverridingConfigurationPropertiesUnitTest.java
@@ -17,17 +17,17 @@ import org.springframework.test.context.junit.jupiter.SpringExtension;
 @TestPropertySource(properties = { "validate.mail_config.address=new_user@test" })
 public class OverridingConfigurationPropertiesUnitTest {
 
-	@Autowired
-	private MailServer mailServer;
+    @Autowired
+    private MailServer mailServer;
 
-	@Test
-	void givenUsingPropertiesAttribute_whenAssiginingNewValueToProprty_thenSpringUsesNewValue() {
+    @Test
+    void givenUsingPropertiesAttribute_whenAssiginingNewValueToProprty_thenSpringUsesNewValue() {
+        assertEquals("new_user@test", mailServer.getMailConfig()
+            .getAddress());
 
-		assertEquals("new_user@test", mailServer.getMailConfig().getAddress());
-
-		Map<String, String> expectedMap = new HashMap<>();
-		expectedMap.put("first", "prop1");
-		expectedMap.put("second", "prop2");
-		assertEquals(expectedMap, mailServer.getPropertiesMap());
-	}
+        Map<String, String> expectedMap = new HashMap<>();
+        expectedMap.put("first", "prop1");
+        expectedMap.put("second", "prop2");
+        assertEquals(expectedMap, mailServer.getPropertiesMap());
+    }
 }
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/PropertyValidationUnitTest.java b/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/PropertyValidationUnitTest.java
index 8833011425..939471dd67 100644
--- a/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/PropertyValidationUnitTest.java
+++ b/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/PropertyValidationUnitTest.java
@@ -18,20 +18,22 @@ import org.springframework.test.context.junit.jupiter.SpringExtension;
 @TestPropertySource("classpath:property-validation-test.properties")
 public class PropertyValidationUnitTest {
 
-	@Autowired
-	private MailServer mailServer;
+    @Autowired
+    private MailServer mailServer;
 
-	private static Validator propertyValidator;
+    private static Validator propertyValidator;
 
-	@BeforeAll
-	public static void setup() {
-		propertyValidator = Validation.buildDefaultValidatorFactory().getValidator();
-	}
+    @BeforeAll
+    public static void setup() {
+        propertyValidator = Validation.buildDefaultValidatorFactory()
+            .getValidator();
+    }
 
-	@Test
-	void whenBindingPropertiesToValidatedBeans_thenConstrainsAreChecked() {
-
-		assertEquals(0, propertyValidator.validate(mailServer.getPropertiesMap()).size());
-		assertEquals(0, propertyValidator.validate(mailServer.getMailConfig()).size());
-	}
+    @Test
+    void whenBindingPropertiesToValidatedBeans_thenConstrainsAreChecked() {
+        assertEquals(0, propertyValidator.validate(mailServer.getPropertiesMap())
+            .size());
+        assertEquals(0, propertyValidator.validate(mailServer.getMailConfig())
+            .size());
+    }
 }
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/SpringPropertiesConversionUnitTest.java b/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/SpringPropertiesConversionUnitTest.java
index d24d563de4..3f2da2a669 100644
--- a/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/SpringPropertiesConversionUnitTest.java
+++ b/spring-boot-modules/spring-boot-testing/src/test/java/com/baeldung/boot/configurationproperties/SpringPropertiesConversionUnitTest.java
@@ -19,27 +19,26 @@ import org.springframework.util.unit.DataSize;
 @TestPropertySource("classpath:spring-conversion-test.properties")
 public class SpringPropertiesConversionUnitTest {
 
-	@Autowired
-	private PropertyConversion propertyConversion;
+    @Autowired
+    private PropertyConversion propertyConversion;
 
-	@Test
-	void whenUsingSpringDefaultSizeConversion_thenDataSizeObjectIsSet() {
+    @Test
+    void whenUsingSpringDefaultSizeConversion_thenDataSizeObjectIsSet() {
+        assertEquals(DataSize.ofMegabytes(500), propertyConversion.getUploadSpeed());
+        assertEquals(DataSize.ofGigabytes(10), propertyConversion.getDownloadSpeed());
+    }
 
-		assertEquals(DataSize.ofMegabytes(500), propertyConversion.getUploadSpeed());
-		assertEquals(DataSize.ofGigabytes(10), propertyConversion.getDownloadSpeed());
-	}
+    @Test
+    void whenUsingSpringDefaultDurationConversion_thenDurationObjectIsSet() {
+        assertEquals(Duration.ofDays(1), propertyConversion.getBackupDay());
+        assertEquals(Duration.ofHours(8), propertyConversion.getBackupHour());
+    }
 
-	@Test
-	void whenUsingSpringDefaultDurationConversion_thenDurationObjectIsSet() {
-
-		assertEquals(Duration.ofDays(1), propertyConversion.getBackupDay());
-		assertEquals(Duration.ofHours(8), propertyConversion.getBackupHour());
-	}
-
-	@Test
-	void whenRegisteringCustomCredentialsConverter_thenCredentialsAreParsed() {
-
-		assertEquals("user", propertyConversion.getCredentials().getUsername());
-		assertEquals("123", propertyConversion.getCredentials().getPassword());
-	}
+    @Test
+    void whenRegisteringCustomCredentialsConverter_thenCredentialsAreParsed() {
+        assertEquals("user", propertyConversion.getCredentials()
+            .getUsername());
+        assertEquals("123", propertyConversion.getCredentials()
+            .getPassword());
+    }
 }
\ No newline at end of file
diff --git a/spring-boot-modules/spring-boot-testing/src/test/resources/application.yml b/spring-boot-modules/spring-boot-testing/src/test/resources/application.yml
index 7dfd4d98a8..1b46b0f1ff 100644
--- a/spring-boot-modules/spring-boot-testing/src/test/resources/application.yml
+++ b/spring-boot-modules/spring-boot-testing/src/test/resources/application.yml
@@ -4,7 +4,7 @@ server:
    address:
       ip: 192.168.0.4
    resources_path:
-      imgs: /etc/test/imgs      
+      imgs: /etc/test/imgs
 ---
 spring:
    profiles: dev