Replaced zero equality checks with isEmpty() method.

L2J_Mobius_2.5_Underground/java/com/l2jmobius/gameserver/instancemanager/PetitionManager.java

@@ -368,7 +368,7 @@ public final class PetitionManager
 		
 		final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm");
 		
-		if (_pendingPetitions.size() == 0)
+		if (_pendingPetitions.isEmpty())
 		{
 			htmlContent.append("<tr><td>There are no currently pending petitions.</td></tr>");
 		}

L2J_Mobius_2.5_Underground/java/com/l2jmobius/gameserver/util/cron4j/CronParser.java

@@ -278,7 +278,7 @@ public class CronParser
 	public static void parseLine(TaskTable table, String line) throws Exception
 	{
 		line = line.trim();
-		if ((line.length() == 0) || (line.charAt(0) == '#'))
+		if ((line.isEmpty()) || (line.charAt(0) == '#'))
 		{
 			return;
 		}
@@ -436,7 +436,7 @@ public class CronParser
 		{
 			// Java inner-process.
 			String className = command.substring(5);
-			if (className.length() == 0)
+			if (className.isEmpty())
 			{
 				throw new Exception("Invalid Java class name on line: " + line);
 			}
@@ -450,7 +450,7 @@ public class CronParser
 			{
 				methodName = className.substring(sep + 1);
 				className = className.substring(0, sep);
-				if (methodName.length() == 0)
+				if (methodName.isEmpty())
 				{
 					throw new Exception("Invalid Java method name on line: " + line);
 				}

L2J_Mobius_2.5_Underground/java/com/l2jmobius/gameserver/util/exp4j/ExpressionBuilder.java

@@ -44,7 +44,7 @@ public class ExpressionBuilder
 	 */
 	public ExpressionBuilder(String expression)
 	{
-		if ((expression == null) || (expression.trim().length() == 0))
+		if ((expression == null) || (expression.trim().isEmpty()))
 		{
 			throw new IllegalArgumentException("Expression can not be empty");
 		}
@@ -190,7 +190,7 @@ public class ExpressionBuilder
 	 */
 	public Expression build()
 	{
-		if (expression.length() == 0)
+		if (expression.isEmpty())
 		{
 			throw new IllegalArgumentException("The expression can not be empty");
 		}