Program: 190341
Project: 190341
Buggy source:
private void parseEdges(NodeList edgeListE,String parent){
  for (int i=0; i < edgeListE.getLength(); i++) {
    Element edgeE=(Element)edgeListE.item(i);
    EdgeDraft edge=container.factory().newEdgeDraft();
    if (parent == null) {
      Progress.progress(progressTicket);
    }
    if (cancel) {
      return;
    }
    String edgeId=edgeE.getAttribute("String_Node_Str");
    if (edgeId.isEmpty()) {
      report.logIssue(new Issue(NbBundle.getMessage(ImporterGEXF.class,"String_Node_Str"),Issue.Level.WARNING));
    }
    String edgeSource=edgeE.getAttribute("String_Node_Str");
    String edgeTarget=edgeE.getAttribute("String_Node_Str");
    NodeDraft nodeSource=container.getNode(edgeSource);
    NodeDraft nodeTarget=container.getNode(edgeTarget);
    if (nodeSource == null || nodeTarget == null) {
      throw new NullPointerException(edgeSource + "String_Node_Str" + edgeTarget);
    }
    edge.setSource(nodeSource);
    edge.setTarget(nodeTarget);
    String edgeType=edgeE.getAttribute("String_Node_Str");
    if (!edgeType.isEmpty()) {
      if (edgeType.equals("String_Node_Str")) {
        edge.setType(EdgeDraft.EdgeType.UNDIRECTED);
      }
 else       if (edgeType.equals("String_Node_Str")) {
        edge.setType(EdgeDraft.EdgeType.DIRECTED);
      }
 else       if (edgeType.equals("String_Node_Str")) {
        edge.setType(EdgeDraft.EdgeType.MUTUAL);
      }
 else {
        report.logIssue(new Issue(NbBundle.getMessage(ImporterGEXF.class,"String_Node_Str",edgeType,edgeId),Issue.Level.SEVERE));
      }
    }
    String weightStr=edgeE.getAttribute("String_Node_Str");
    if (!weightStr.isEmpty()) {
      try {
        float weight=Float.parseFloat(weightStr);
        edge.setWeight(weight);
      }
 catch (      NumberFormatException e) {
        report.logIssue(new Issue(NbBundle.getMessage(ImporterGEXF.class,"String_Node_Str",edgeId),Issue.Level.WARNING));
      }
    }
    String edgeLabel=edgeE.getAttribute("String_Node_Str");
    if (!edgeLabel.isEmpty()) {
      edge.setLabel(edgeLabel);
    }
    Node child=edgeE.getFirstChild();
    if (child != null) {
      do {
        if (child.getNodeName().equals("String_Node_Str")) {
          Node childE=child.getFirstChild();
          if (childE != null) {
            do {
              if (childE.getNodeName().equals("String_Node_Str")) {
                Element dataE=(Element)childE;
                setEdgeData(dataE,edge,edgeId);
              }
            }
 while ((childE=childE.getNextSibling()) != null);
          }
        }
      }
 while ((child=child.getNextSibling()) != null);
    }
    if (isDynamicMode) {
      String edgeStart=null;
      String edgeEnd=null;
      if (!edgeE.getAttribute("String_Node_Str").isEmpty()) {
        edgeStart=edgeE.getAttribute("String_Node_Str");
      }
      if (!edgeE.getAttribute("String_Node_Str").isEmpty()) {
        edgeEnd=edgeE.getAttribute("String_Node_Str");
      }
      if (edgeStart != null || edgeEnd != null) {
        edge.addTimeSlice(edgeStart,edgeEnd);
      }
    }
    container.addEdge(edge);
  }
}

Fixed version (ground truth):
private void parseEdges(NodeList edgeListE,String parent){
  for (int i=0; i < edgeListE.getLength(); i++) {
    if (edgeListE.item(i).getNodeType() != ELEMENT_NODE) {
      continue;
    }
    Element edgeE=(Element)edgeListE.item(i);
    EdgeDraft edge=container.factory().newEdgeDraft();
    if (parent == null) {
      Progress.progress(progressTicket);
    }
    if (cancel) {
      return;
    }
    String edgeId=edgeE.getAttribute("String_Node_Str");
    if (edgeId.isEmpty()) {
      report.logIssue(new Issue(NbBundle.getMessage(ImporterGEXF.class,"String_Node_Str"),Issue.Level.WARNING));
    }
    String edgeSource=edgeE.getAttribute("String_Node_Str");
    String edgeTarget=edgeE.getAttribute("String_Node_Str");
    NodeDraft nodeSource=container.getNode(edgeSource);
    NodeDraft nodeTarget=container.getNode(edgeTarget);
    if (nodeSource == null || nodeTarget == null) {
      throw new NullPointerException(edgeSource + "String_Node_Str" + edgeTarget);
    }
    edge.setSource(nodeSource);
    edge.setTarget(nodeTarget);
    String edgeType=edgeE.getAttribute("String_Node_Str");
    if (!edgeType.isEmpty()) {
      if (edgeType.equals("String_Node_Str")) {
        edge.setType(EdgeDraft.EdgeType.UNDIRECTED);
      }
 else       if (edgeType.equals("String_Node_Str")) {
        edge.setType(EdgeDraft.EdgeType.DIRECTED);
      }
 else       if (edgeType.equals("String_Node_Str")) {
        edge.setType(EdgeDraft.EdgeType.MUTUAL);
      }
 else {
        report.logIssue(new Issue(NbBundle.getMessage(ImporterGEXF.class,"String_Node_Str",edgeType,edgeId),Issue.Level.SEVERE));
      }
    }
    String weightStr=edgeE.getAttribute("String_Node_Str");
    if (!weightStr.isEmpty()) {
      try {
        float weight=Float.parseFloat(weightStr);
        edge.setWeight(weight);
      }
 catch (      NumberFormatException e) {
        report.logIssue(new Issue(NbBundle.getMessage(ImporterGEXF.class,"String_Node_Str",edgeId),Issue.Level.WARNING));
      }
    }
    String edgeLabel=edgeE.getAttribute("String_Node_Str");
    if (!edgeLabel.isEmpty()) {
      edge.setLabel(edgeLabel);
    }
    Node child=edgeE.getFirstChild();
    if (child != null) {
      do {
        if (child.getNodeName().equals("String_Node_Str")) {
          Node childE=child.getFirstChild();
          if (childE != null) {
            do {
              if (childE.getNodeName().equals("String_Node_Str")) {
                Element dataE=(Element)childE;
                setEdgeData(dataE,edge,edgeId);
              }
            }
 while ((childE=childE.getNextSibling()) != null);
          }
        }
      }
 while ((child=child.getNextSibling()) != null);
    }
    if (isDynamicMode) {
      String edgeStart=null;
      String edgeEnd=null;
      if (!edgeE.getAttribute("String_Node_Str").isEmpty()) {
        edgeStart=edgeE.getAttribute("String_Node_Str");
      }
      if (!edgeE.getAttribute("String_Node_Str").isEmpty()) {
        edgeEnd=edgeE.getAttribute("String_Node_Str");
      }
      if (edgeStart != null || edgeEnd != null) {
        edge.addTimeSlice(edgeStart,edgeEnd);
      }
    }
    container.addEdge(edge);
  }
}