diff --git a/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/dao/JdbcTaskExecutionDao.java b/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/dao/JdbcTaskExecutionDao.java
index 5594b3ea..0aa3e186 100644
--- a/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/dao/JdbcTaskExecutionDao.java
+++ b/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/dao/JdbcTaskExecutionDao.java
@@ -26,6 +26,7 @@ import java.util.Collections;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeSet;
@@ -527,7 +528,7 @@ public class JdbcTaskExecutionDao implements TaskExecutionDao {
 
 		if (sort != null) {
 			for (Sort.Order sortOrder : sort) {
-				if (validSortColumns.contains(sortOrder.getProperty().toUpperCase())) {
+				if (validSortColumns.contains(sortOrder.getProperty().toUpperCase(Locale.ROOT))) {
 					sortOrderMap.put(sortOrder.getProperty(),
 							sortOrder.isAscending() ? Order.ASCENDING : Order.DESCENDING);
 				}
diff --git a/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/database/support/AbstractSqlPagingQueryProvider.java b/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/database/support/AbstractSqlPagingQueryProvider.java
index 2daa6c60..631a47e6 100644
--- a/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/database/support/AbstractSqlPagingQueryProvider.java
+++ b/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/database/support/AbstractSqlPagingQueryProvider.java
@@ -19,6 +19,7 @@ package org.springframework.cloud.task.repository.database.support;
 import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 
 import javax.sql.DataSource;
@@ -157,7 +158,7 @@ public abstract class AbstractSqlPagingQueryProvider implements PagingQueryProvi
 	private String removeKeyWord(String keyWord, String clause) {
 		String temp = clause.trim();
 		String keyWordString = keyWord + " ";
-		if (temp.toLowerCase().startsWith(keyWordString) && temp.length() > keyWordString.length()) {
+		if (temp.toLowerCase(Locale.ROOT).startsWith(keyWordString) && temp.length() > keyWordString.length()) {
 			return temp.substring(keyWordString.length());
 		}
 		else {
diff --git a/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/database/support/SqlPagingQueryProviderFactoryBean.java b/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/database/support/SqlPagingQueryProviderFactoryBean.java
index b9ce01ea..ad1daab7 100755
--- a/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/database/support/SqlPagingQueryProviderFactoryBean.java
+++ b/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/database/support/SqlPagingQueryProviderFactoryBean.java
@@ -17,6 +17,7 @@
 package org.springframework.cloud.task.repository.database.support;
 
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 
 import javax.sql.DataSource;
@@ -135,7 +136,7 @@ public class SqlPagingQueryProviderFactoryBean implements FactoryBean<PagingQuer
 
 		DatabaseType type;
 		try {
-			type = this.databaseType != null ? DatabaseType.valueOf(this.databaseType.toUpperCase())
+			type = this.databaseType != null ? DatabaseType.valueOf(this.databaseType.toUpperCase(Locale.ROOT))
 					: DatabaseType.fromMetaData(this.dataSource);
 		}
 		catch (MetaDataAccessException e) {
diff --git a/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/support/TaskRepositoryInitializer.java b/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/support/TaskRepositoryInitializer.java
index 82071ab4..c09a5161 100644
--- a/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/support/TaskRepositoryInitializer.java
+++ b/spring-cloud-task-core/src/main/java/org/springframework/cloud/task/repository/support/TaskRepositoryInitializer.java
@@ -17,6 +17,7 @@
 package org.springframework.cloud.task.repository.support;
 
 import java.sql.SQLException;
+import java.util.Locale;
 
 import javax.sql.DataSource;
 
@@ -84,7 +85,8 @@ public final class TaskRepositoryInitializer implements InitializingBean {
 
 	private String getDatabaseType(DataSource dataSource) {
 		try {
-			return JdbcUtils.commonDatabaseName(DatabaseType.fromMetaData(dataSource).toString()).toLowerCase();
+			return JdbcUtils.commonDatabaseName(DatabaseType.fromMetaData(dataSource).toString())
+				.toLowerCase(Locale.ROOT);
 		}
 		catch (MetaDataAccessException ex) {
 			throw new IllegalStateException("Unable to detect database type", ex);