Program: 11501
Project: 11501
Buggy source:
/** 
 * Initializes this operator and sets the one and only target product. <p>The target product can be either defined by a field of type   {@link org.esa.beam.framework.datamodel.Product} annotated with the{@link org.esa.beam.framework.gpf.annotations.TargetProduct TargetProduct} annotation orby calling  {@link #setTargetProduct} method.</p><p>The framework calls this method after it has created this operator. Any client code that must be performed before computation of tile data should be placed here.</p>
 * @throws org.esa.beam.framework.gpf.OperatorException If an error occurs during operator initialisation.
 * @see #getTargetProduct()
 */
@Override public void initialize() throws OperatorException {
  try {
    if (doNotSubtract) {
      productName="String_Node_Str";
      productTag="String_Node_Str";
    }
 else {
      productName="String_Node_Str";
      productTag="String_Node_Str";
    }
    constructSourceMetadata();
    constructTargetMetadata();
    createTargetProduct();
    getSourceImageDimension();
    if (!doNotSubtract) {
      final InputProductValidator validator=new InputProductValidator(sourceProduct);
      validator.checkIfCoregisteredStack();
      isTOPSARBurstProduct=validator.isTOPSARBurstProduct();
      if (isTOPSARBurstProduct) {
        su=new Sentinel1Utils(sourceProduct);
        subSwath=su.getSubSwath();
        numSubSwaths=su.getNumOfSubSwath();
        subSwathIndex=1;
        getMstApproxSceneCentreXYZ();
        getSlvApproxSceneCentreAzimuthTime();
        constructFlatEarthPolynomialsForTOPSARProduct();
      }
 else {
        constructFlatEarthPolynomials();
      }
    }
  }
 catch (  Exception e) {
    throw new OperatorException(e);
  }
}

Fixed version (ground truth):
/** 
 * Initializes this operator and sets the one and only target product. <p>The target product can be either defined by a field of type   {@link org.esa.beam.framework.datamodel.Product} annotated with the{@link org.esa.beam.framework.gpf.annotations.TargetProduct TargetProduct} annotation orby calling  {@link #setTargetProduct} method.</p><p>The framework calls this method after it has created this operator. Any client code that must be performed before computation of tile data should be placed here.</p>
 * @throws org.esa.beam.framework.gpf.OperatorException If an error occurs during operator initialisation.
 * @see #getTargetProduct()
 */
@Override public void initialize() throws OperatorException {
  try {
    if (doNotSubtract) {
      productName="String_Node_Str";
      productTag="String_Node_Str";
    }
 else {
      productName="String_Node_Str";
      productTag="String_Node_Str";
    }
    final InputProductValidator validator=new InputProductValidator(sourceProduct);
    validator.checkIfCoregisteredStack();
    isTOPSARBurstProduct=validator.isTOPSARBurstProduct();
    if (isTOPSARBurstProduct) {
      final String topsarTag=getTOPSARTag(sourceProduct);
      productTag=topsarTag + "String_Node_Str" + productTag;
    }
    constructSourceMetadata();
    constructTargetMetadata();
    createTargetProduct();
    getSourceImageDimension();
    if (!doNotSubtract) {
      if (isTOPSARBurstProduct) {
        su=new Sentinel1Utils(sourceProduct);
        subSwath=su.getSubSwath();
        numSubSwaths=su.getNumOfSubSwath();
        subSwathIndex=1;
        getMstApproxSceneCentreXYZ();
        getSlvApproxSceneCentreAzimuthTime();
        constructFlatEarthPolynomialsForTOPSARProduct();
      }
 else {
        constructFlatEarthPolynomials();
      }
    }
  }
 catch (  Exception e) {
    throw new OperatorException(e);
  }
}