Project Configurator for Jira Server and DC

java.lang.NumberFormatException - Null Within SpringImportHandler

Problem: This error occurs while importing Sprint data as can be seen at the top of the error trace:

Data import failed with exception: null
java.lang.NumberFormatException: null
at java.lang.Long.parseLong(Long.java:552)
at java.lang.Long.valueOf(Long.java:803)
at com.atlassian.greenhopper.imports.SprintImportHandler.endTable(SprintImportHandler.java:105)
at com.atlassian.jira.imports.project.ao.handler.ChainedAoSaxHandler.endTable(ChainedAoSaxHandler.java:263)
at com.atlassian.jira.imports.project.ao.handler.ChainedAoSaxHandler.endElement(ChainedAoSaxHandler.java:190)
at com.atlassian.jira.imports.project.ao.handler.ChainedAoSaxHandler.endElement(ChainedAoSaxHandler.java:151)

Solution: The Jira knowledge base article, Project Import fails with Unexpected import failure, describes this issue, points to the bug ticket with the root cause and recommends how to fix it.