anchor.diff:  
   [source,xml,linenums]
   ----
  -<serviceTask id="javaService" 
  -    name="Java service invocation" 
  +<serviceTask id="javaService"
  +    name="Java service invocation"
       activiti:class="org.activiti.examples.bpmn.servicetask.ToUpperCaseFieldInjected">
  -  <extensionElements>   
  +  <extensionElements>
       <activiti:field name="text">
           <activiti:string>
             Hello World
         </activiti:string>
       </activiti:field>
  -  </extensionElements>        
  -</serviceTask>        
  +  </extensionElements>
  +</serviceTask>
   ----
   
   To inject values that are dynamically resolved at runtime, expressions can be used. Those expressions can use process variables, or Spring defined beans (if Spring is used). As noted in <<bpmnJavaServiceTaskImplementation,Service Task Implementation>>, an instance of the Java class is shared among all process-instances in a service task. To have dynamic injection of values in fields, you can inject value and method expressions in a +org.activiti.engine.delegate.Expression+ which can be evaluated/invoked using the +DelegateExecution+ passed in the +execute+ method.
   
   [source,xml,linenums]
   ----
  -<serviceTask id="javaService" name="Java service invocation" 
  +<serviceTask id="javaService" name="Java service invocation"
     activiti:class="org.activiti.examples.bpmn.servicetask.ReverseStringsFieldInjected">
  -  
  +
     <extensionElements>
       <activiti:field name="text1">
         <activiti:expression>${genderBean.getGenderString(gender)}</activiti:expression>
  
positive.code: <process id="SimpleCamelCallProcess">
    <startEvent id="start"/>
    <sequenceFlow id="flow1" sourceRef="start" targetRef="simpleCall"/>
    
    <serviceTask id="simpleCall" activiti:type="camel"/>
    
    <sequenceFlow id="flow2" sourceRef="simpleCall" targetRef="end"/>      
    <endEvent id="end"/>
  </process>       
  ----
  
  
  
negative.code:       <activiti:field name="dynamicValue" expression="${myVar}" />
      </activiti:executionListener>
    </extensionElements>
  
    <startEvent id="theStart" />
    <sequenceFlow sourceRef="theStart" targetRef="firstTask" />
  
    <userTask id="firstTask" />
    <sequenceFlow sourceRef="firstTask" targetRef="theEnd" />
  
    <endEvent id="theEnd" />
  </process>
  ----
  