Program: 115646
Project: 115646
Buggy source:
/** 
 * Creates the group instance and adds the required context objects
 * @param group                             the group
 * @param parentInstanceContext             the parent instance context
 * @param partitionContext                  partition-context used to create the group instance
 * @param parentLevelNetworkPartitionContext the group level network partition context
 */
private String createGroupInstanceAndAddToMonitor(Group group,Instance parentInstanceContext,PartitionContext partitionContext,ParentLevelNetworkPartitionContext parentLevelNetworkPartitionContext,GroupInstance groupInstance){
  String partitionId=null;
  if (groupInstance == null) {
    if (partitionContext != null) {
      partitionId=partitionContext.getPartitionId();
    }
    groupInstance=createGroupInstance(group,parentInstanceContext.getNetworkPartitionId(),parentInstanceContext.getInstanceId(),partitionId);
  }
  this.addInstance(groupInstance);
  String instanceId=groupInstance.getInstanceId();
  GroupInstanceContext groupInstanceContext=new GroupInstanceContext(instanceId);
  groupInstanceContext.setParentInstanceId(groupInstance.getParentId());
  groupInstanceContext.addPartitionContext((GroupLevelPartitionContext)partitionContext);
  parentLevelNetworkPartitionContext.addInstanceContext(groupInstanceContext);
  parentLevelNetworkPartitionContext.addPendingInstance(groupInstanceContext);
  if (log.isInfoEnabled()) {
    log.info("String_Node_Str" + instanceId + "String_Node_Str"+ this.id);
  }
  if (partitionContext != null) {
    ((GroupLevelPartitionContext)partitionContext).addActiveInstance(groupInstance);
  }
  return instanceId;
}

Fixed version (ground truth):
/** 
 * Creates the group instance and adds the required context objects
 * @param group                              the group
 * @param parentInstanceContext              the parent instance context
 * @param partitionContext                   partition-context used to create the group instance
 * @param parentLevelNetworkPartitionContext the group level network partition context
 */
private String createGroupInstanceAndAddToMonitor(Group group,Instance parentInstanceContext,PartitionContext partitionContext,ParentLevelNetworkPartitionContext parentLevelNetworkPartitionContext,GroupInstance groupInstance){
  String partitionId=null;
  if (groupInstance == null) {
    if (partitionContext != null) {
      partitionId=partitionContext.getPartitionId();
    }
    groupInstance=createGroupInstance(group,parentInstanceContext.getNetworkPartitionId(),parentInstanceContext.getInstanceId(),partitionId);
  }
  this.addInstance(groupInstance);
  String instanceId=groupInstance.getInstanceId();
  GroupInstanceContext groupInstanceContext=new GroupInstanceContext(instanceId);
  groupInstanceContext.setParentInstanceId(groupInstance.getParentId());
  groupInstanceContext.addPartitionContext((GroupLevelPartitionContext)partitionContext);
  parentLevelNetworkPartitionContext.addInstanceContext(groupInstanceContext);
  parentLevelNetworkPartitionContext.addPendingInstance(groupInstanceContext);
  if (log.isInfoEnabled()) {
    log.info("String_Node_Str" + instanceId + "String_Node_Str"+ this.id);
  }
  if (partitionContext != null) {
    ((GroupLevelPartitionContext)partitionContext).addActiveInstance(groupInstance);
  }
  return instanceId;
}