How to use process variables in Camunda-bpm?
<p>I'm new to Camunda and didn't find any tutorial or reference explaining how to achieve the following:
I have a simple bpmn process in which I am using a service task. I want to execute my process by using processEngine.getRuntimeService().startProcessInstanceByKey("Process_1", variables);
where my variables are as follows:</p>

<pre><code>Map variables = new HashMap();
variables.put("a", 2);
variables.put("b", 5);
</code></pre>

<p>Now my service task is implementing a java class in which I want to use to process variables "a" and "b"?</p>

<p>How can I get the same process variables "a" and "b" in that class?</p>