Use String#isEmpty

Signed-off-by: Tran Ngoc Nhan <ngocnhan.tran1996@gmail.com>

web/src/main/java/org/springframework/security/web/authentication/rememberme/AbstractRememberMeServices.java

@@ -130,7 +130,7 @@ public abstract class AbstractRememberMeServices
 			return null;
 		}
 		this.logger.debug("Remember-me cookie detected");
-		if (rememberMeCookie.length() == 0) {
+		if (rememberMeCookie.isEmpty()) {
 			this.logger.debug("Cookie was empty");
 			cancelCookie(request, response);
 			return null;
@@ -383,7 +383,7 @@ public abstract class AbstractRememberMeServices
 
 	private String getCookiePath(HttpServletRequest request) {
 		String contextPath = request.getContextPath();
-		return (contextPath.length() > 0) ? contextPath : "/";
+		return contextPath.isEmpty() ? "/" : contextPath;
 	}
 
 	/**

web/src/main/java/org/springframework/security/web/firewall/RequestWrapper.java

@@ -57,7 +57,7 @@ final class RequestWrapper extends FirewalledRequest {
 		super(request);
 		this.strippedServletPath = strip(request.getServletPath());
 		String pathInfo = strip(request.getPathInfo());
-		if (pathInfo != null && pathInfo.length() == 0) {
+		if (pathInfo != null && pathInfo.isEmpty()) {
 			pathInfo = null;
 		}
 		this.strippedPathInfo = pathInfo;

web/src/main/java/org/springframework/security/web/savedrequest/DefaultSavedRequest.java

@@ -321,7 +321,7 @@ public class DefaultSavedRequest implements SavedRequest {
 		if (matchingRequestParameterName == null) {
 			return queryString;
 		}
-		if (queryString == null || queryString.length() == 0) {
+		if (queryString == null || queryString.isEmpty()) {
 			return matchingRequestParameterName;
 		}
 		return UriComponentsBuilder.newInstance()

web/src/main/java/org/springframework/security/web/util/TextEscapeUtils.java

@@ -25,7 +25,7 @@ package org.springframework.security.web.util;
 public abstract class TextEscapeUtils {
 
 	public static String escapeEntities(String s) {
-		if (s == null || s.length() == 0) {
+		if (s == null || s.isEmpty()) {
 			return s;
 		}
 		StringBuilder sb = new StringBuilder();

web/src/test/java/org/springframework/security/web/firewall/RequestWrapperTests.java

@@ -73,7 +73,7 @@ public class RequestWrapperTests {
 			String path = entry.getKey();
 			String expectedResult = entry.getValue();
 			// Should be null when stripped value is empty
-			if (expectedResult.length() == 0) {
+			if (expectedResult.isEmpty()) {
 				expectedResult = null;
 			}
 			request.setPathInfo(path);