Improve performance of some string operations

Issue: SPR-16293

spring-beans/src/main/java/org/springframework/beans/CachedIntrospectionResults.java

@@ -341,10 +341,10 @@ public class CachedIntrospectionResults {
 	PropertyDescriptor getPropertyDescriptor(String name) {
 		PropertyDescriptor pd = this.propertyDescriptorCache.get(name);
 		if (pd == null && StringUtils.hasLength(name)) {
-			// Same lenient fallback checking as in PropertyTypeDescriptor...
-			pd = this.propertyDescriptorCache.get(name.substring(0, 1).toLowerCase() + name.substring(1));
+			// Same lenient fallback checking as in Property...
+			pd = this.propertyDescriptorCache.get(StringUtils.uncapitalize(name));
 			if (pd == null) {
-				pd = this.propertyDescriptorCache.get(name.substring(0, 1).toUpperCase() + name.substring(1));
+				pd = this.propertyDescriptorCache.get(StringUtils.capitalize(name));
 			}
 		}
 		return (pd == null || pd instanceof GenericTypeAwarePropertyDescriptor ? pd :

spring-core/src/main/java/org/springframework/core/convert/Property.java

@@ -239,11 +239,9 @@ public final class Property {
 			field = ReflectionUtils.findField(declaringClass, name);
 			if (field == null) {
 				// Same lenient fallback checking as in CachedIntrospectionResults...
-				field = ReflectionUtils.findField(declaringClass,
-						name.substring(0, 1).toLowerCase() + name.substring(1));
+				field = ReflectionUtils.findField(declaringClass, StringUtils.uncapitalize(name));
 				if (field == null) {
-					field = ReflectionUtils.findField(declaringClass,
-							name.substring(0, 1).toUpperCase() + name.substring(1));
+					field = ReflectionUtils.findField(declaringClass, StringUtils.capitalize(name));
 				}
 			}
 		}

spring-core/src/main/java/org/springframework/core/io/support/PathMatchingResourcePatternResolver.java

@@ -427,7 +427,7 @@ public class PathMatchingResourcePatternResolver implements ResourcePatternResol
 					int prefixIndex = filePath.indexOf(':');
 					if (prefixIndex == 1) {
 						// Possibly "c:" drive prefix on Windows, to be upper-cased for proper duplicate detection
-						filePath = filePath.substring(0, 1).toUpperCase() + filePath.substring(1);
+						filePath = StringUtils.capitalize(filePath);
 					}
 					UrlResource jarResource = new UrlResource(ResourceUtils.JAR_URL_PREFIX +
 							ResourceUtils.FILE_URL_PREFIX + filePath + ResourceUtils.JAR_URL_SEPARATOR);

spring-jdbc/src/main/java/org/springframework/jdbc/support/JdbcUtils.java

@@ -469,24 +469,24 @@ public abstract class JdbcUtils {
 		StringBuilder result = new StringBuilder();
 		boolean nextIsUpper = false;
 		if (name != null && name.length() > 0) {
-			if (name.length() > 1 && name.substring(1, 2).equals("_")) {
-				result.append(name.substring(0, 1).toUpperCase());
+			if (name.length() > 1 && name.charAt(1) == '_') {
+				result.append(Character.toUpperCase(name.charAt(0)));
 			}
 			else {
-				result.append(name.substring(0, 1).toLowerCase());
+				result.append(Character.toLowerCase(name.charAt(0)));
 			}
 			for (int i = 1; i < name.length(); i++) {
-				String s = name.substring(i, i + 1);
-				if (s.equals("_")) {
+				char c = name.charAt(i);
+				if (c == '_') {
 					nextIsUpper = true;
 				}
 				else {
 					if (nextIsUpper) {
-						result.append(s.toUpperCase());
+						result.append(Character.toUpperCase(c));
 						nextIsUpper = false;
 					}
 					else {
-						result.append(s.toLowerCase());
+						result.append(Character.toLowerCase(c));
 					}
 				}
 			}

spring-web/src/main/java/org/springframework/web/multipart/support/StandardServletMultipartResolver.java

@@ -21,6 +21,7 @@ import javax.servlet.http.Part;
 
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.util.StringUtils;
 import org.springframework.web.multipart.MultipartException;
 import org.springframework.web.multipart.MultipartHttpServletRequest;
 import org.springframework.web.multipart.MultipartResolver;
@@ -67,11 +68,11 @@ public class StandardServletMultipartResolver implements MultipartResolver {
 	@Override
 	public boolean isMultipart(HttpServletRequest request) {
 		// Same check as in Commons FileUpload...
-		if (!"post".equals(request.getMethod().toLowerCase())) {
+		if (!"post".equalsIgnoreCase(request.getMethod())) {
 			return false;
 		}
 		String contentType = request.getContentType();
-		return (contentType != null && contentType.toLowerCase().startsWith("multipart/"));
+		return StringUtils.startsWithIgnoreCase(contentType, "multipart/");
 	}
 
 	@Override