Calling soapUI groovy script from Java

I am using soapui open source and am trying to run a soapui groovy script  test step via Java.  The groovy script opens a file to read data and then the appropriate test cases run. When i call this test step from Java, the call is successful, however the groovy script fails to read the file data and i am not able to run the test cases properly.

Could anyone please suggest a solution for this?

This is my java code :

WsdlProject project = new WsdlProject("Path to project");
WsdlTestCase testCase = project.getTestSuiteByName("...").getTestCaseByName("...");
WsdlTestStep testStep = testCase.getTestStepByName("<Script name>");
WsdlTestCaseRunner runner = new WsdlTestCaseRunner(testCase, new StringToObjectMap());
runner.runTestStep(testStep);