title: groovy.lang.MissingMethodException: No signature of method: java.lang.String.call() is applicable for argument types: () values: []
body: <p>I am trying to access data from <code>RESTAPI</code> using groovy code where i am getting error as below:</p>
  <pre><code>groovy.lang.MissingMethodException: No signature of method: java.lang.String.call() is applicable for argument types: () values: []
  Possible solutions: wait(), chars(), any(), wait(long), take(int), tap(groovy.lang.Closure)
      at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.unwrap(ScriptBytecodeAdapter.java:70)
      at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.invokeMethodN(ScriptBytecodeAdapter.java:182)
      at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.invokeClosure(ScriptBytecodeAdapter.java:586)
  </code></pre>
  <p>The error is coming mostly on the below part of the lines from code :</p>
  <pre><code>    String requestString = getRequestStringPrefix() + sb.toString()
      readHistory(authToken,ricMap,outFile)
      writeInstFile(outFile)
  </code></pre>
  <p>I am really new in the groovy coding and not understanding exactly the cause of the issue and how to resolve this issue in the code.</p>