[MNG-6829] Replace StringUtils#isEmpty(String) and #isNotEmpty(String) (#97)

Continuation of https://issues.apache.org/jira/browse/MNG-6829

Review requested of @elharo

Use this link to re-run the recipe: https://public.moderne.io/recipes/org.openrewrite.java.migrate.apache.commons.lang.IsNotEmptyToJdk?organizationId=QXBhY2hlIE1hdmVu

Co-authored-by: Moderne <[email protected]>

Author: timtebeek

maven-jxr-plugin/src/main/java/org/apache/maven/plugin/jxr/AbstractJxrReport.java

@@ -332,7 +332,7 @@ private String getBottomText()
      */
     private void copyRequiredResources( String dir )
     {
-        if ( StringUtils.isNotEmpty( stylesheet ) )
+        if ( stylesheet != null && !stylesheet.isEmpty() )
         {
             File stylesheetFile = new File( stylesheet );
             File destStylesheetFile = new File( dir, "stylesheet.css" );
@@ -493,7 +493,7 @@ protected void executeReport( Locale locale )
     private String getTemplateDir()
     {
         // Check if overridden
-        if ( StringUtils.isEmpty( templateDir ) )
+        if ( templateDir == null || templateDir.isEmpty() )
         {
             if ( javadocTemplatesVersion.isAtLeast( "1.8" ) )
             {
@@ -524,7 +524,7 @@ private void setJavadocTemplatesVersion()
     {
         JavaVersion javaVersion = JavaVersion.JAVA_SPECIFICATION_VERSION;
 
-        if ( StringUtils.isNotEmpty( javadocVersion ) )
+        if ( javadocVersion != null && !javadocVersion.isEmpty() )
         {
             javadocTemplatesVersion = JavaVersion.parse( javadocVersion );
         }
@@ -592,7 +592,7 @@ private Path getJavadocLocation()
                 // Special case: using the site:stage goal
                 String stagingDirectory = System.getProperty( "stagingDirectory" );
 
-                if ( StringUtils.isNotEmpty( stagingDirectory ) )
+                if ( stagingDirectory != null && !stagingDirectory.isEmpty() )
                 {
                     String javadocDestDir = getJavadocDir().getName();
                     boolean javadocAggregate = JxrReportUtil.isJavadocAggregated( project );

maven-jxr-plugin/src/main/java/org/apache/maven/plugin/jxr/JxrReportUtil.java

@@ -134,7 +134,7 @@ protected static String getMavenJavadocPluginBasicOption( MavenProject project,
             }
 
             String attribute = pluginConf.getAttribute( optionName );
-            if ( StringUtils.isNotEmpty( attribute ) )
+            if ( attribute != null && !attribute.isEmpty() )
             {
                 return attribute;
             }