When Jenkins checkouts a project, this exception occurred.

ERROR: Failed to parse svn info for external http://example.com/foo/bar.xml at ./src\main\resources\foo\bar.xml
org.tmatesoft.svn.core.SVNException: svn: 'C:\Users\a\.jenkins\jobs\test\workspace\.\src\main\resources\foo\bar.xml' is not under version control
at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:64)
at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:51)
at org.tmatesoft.svn.core.wc.SVNWCClient$13.handleError(SVNWCClient.java:3314)
at org.tmatesoft.svn.core.internal.wc.admin.SVNWCAccess.walkEntries(SVNWCAccess.java:758)
at org.tmatesoft.svn.core.internal.wc.admin.SVNWCAccess.walkEntries(SVNWCAccess.java:741)
at org.tmatesoft.svn.core.wc.SVNWCClient.crawlEntries(SVNWCClient.java:3294)
at org.tmatesoft.svn.core.wc.SVNWCClient.doInfo(SVNWCClient.java:2498)
at org.tmatesoft.svn.core.wc.SVNWCClient.doInfo(SVNWCClient.java:2865)
at hudson.scm.SubversionSCM$BuildRevisionMapTask.invoke(SubversionSCM.java:1031)
at hudson.scm.SubversionSCM$BuildRevisionMapTask.invoke(SubversionSCM.java:1001)
at hudson.FilePath.act(FilePath.java:785)
at hudson.FilePath.act(FilePath.java:767)
at hudson.scm.SubversionSCM.checkout(SubversionSCM.java:685)
at hudson.model.AbstractProject.checkout(AbstractProject.java:1195)
at hudson.model.AbstractBuild$AbstractRunner.checkout(AbstractBuild.java:568)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:456)
at hudson.model.Run.run(Run.java:1404)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:230)
Caused by: org.tmatesoft.svn.core.SVNErrorMessage: svn: 'C:\Users\a\.jenkins\jobs\test\workspace\.\src\main\resources\foo\bar.xml' is not under version control
at org.tmatesoft.svn.core.SVNErrorMessage.create(SVNErrorMessage.java:163)
at org.tmatesoft.svn.core.SVNErrorMessage.create(SVNErrorMessage.java:118)

Folder 'foo' is set svn:externals(folder) to the folder named 'foo2' and 'bar.xml' file in foo2 is set svn:externals(file) to 'bar2.xml' in folder named 'foo3'.
foo/bar.xml entries in (project folder)/svnexternals.txt in Jenkins.
But this file was not checkout.

Subversive using SNVKit in Eclipse can checkout this file.