Leve 2

pom.xml

@@ -46,6 +46,10 @@
         <type>pom</type>
         <scope>import</scope>
       </dependency>
+      <dependency>
+        <groupId>org.jenkins-ci.plugins</groupId>
+        <artifactId>structs</artifactId>
+      </dependency>
     </dependencies>
   </dependencyManagement>
 

src/main/java/io/jenkins/plugins/sample/SampleConfiguration.java

@@ -20,6 +20,17 @@ public static SampleConfiguration get() {
     }
 
     private String label;
+    private String description;
+
+    public String getDescription() {
+        return description;
+    }
+
+   @DataBoundSetter
+    public void setDescription(String description) {
+        this.description = description;
+        save();
+    }
 
     public SampleConfiguration() {
         // When Jenkins is restarted, load any saved configuration from disk.
@@ -44,7 +55,16 @@ public void setLabel(String label) {
     public FormValidation doCheckLabel(@QueryParameter String value) {
         if (StringUtils.isEmpty(value)) {
             return FormValidation.warning("Please specify a label.");
+        }else if (!value.matches("[a-zA-Z]")) {
+            return  FormValidation.error("Only lowercase and uppercase ans spaces are allowed");
         }
         return FormValidation.ok();
     }
+    public FormValidation doCheckDescription(@QueryParameter String value) {
+        if (StringUtils.isEmpty(value)) {
+            return FormValidation.warning("Please specify a description.");
+        }
+        return FormValidation.ok();
+    }
+
 }

src/main/resources/io/jenkins/plugins/sample/SampleConfiguration/config.jelly

@@ -5,5 +5,8 @@
         <f:entry field="label" title="${%Label}">
             <f:textbox/>
         </f:entry>
+        <f:entry field="description" title="${%Description}">
+            <f:textarea/>
+        </f:entry>
     </f:section>
 </j:jelly>