If JenkinsLocationConfiguration.jenkinsUrl is still null, CoreEnvironmentContributor will silently skip several variables.
No obvious fix for that, but at least document it so it is not so surprising.

Need to restore the owner of the describable list so that changes in subsequent sessions will be persisted.
(Issue not reproduced here, but was in similar ArtifactManagerConfiguration: 757fe084.)

[JENKINS-19004] set name of remoting threads

OldDataMonitor already collates these errors and presents them to the user with a fix.
Printing a stack trace for each and every missing class just clutters the log file.
(Especially when restarting after disabling a widely-used plugin.)

[GROOVY-4292] Update Groovy to 1.8.9 to avoid random livelock during startup when init.groovy specified.
"GroovyInitScript.init" daemon prio=10 tid=0x00007f28d0001800 nid=0x48 runnable [0x00007f28cb79e000]
   java.lang.Thread.State: RUNNABLE
	at java.util.WeakHashMap.get(Unknown Source)
	at org.codehaus.groovy.ast.ClassHelper.makeCached(ClassHelper.java:121)
	at org.codehaus.groovy.ast.ClassHelper.makeWithoutCaching(ClassHelper.java:183)
	at org.codehaus.groovy.ast.ClassHelper.make(ClassHelper.java:170)
	at org.codehaus.groovy.ast.ClassHelper.make(ClassHelper.java:159)
	at org.codehaus.groovy.vmplugin.v5.Java5.makeClassNode(Java5.java:382)
	at org.codehaus.groovy.vmplugin.v5.Java5.makeParameter(Java5.java:403)
	at org.codehaus.groovy.vmplugin.v5.Java5.makeParameters(Java5.java:396)
	at org.codehaus.groovy.vmplugin.v5.Java5.configureClassNode(Java5.java:331)
	at org.codehaus.groovy.ast.ClassNode.lazyClassInit(ClassNode.java:262)
	- locked <0x00000000f4bfe2b0> (a java.lang.Object)
	at org.codehaus.groovy.ast.ClassNode.getInterfaces(ClassNode.java:356)
	at org.codehaus.groovy.ast.ClassNode.declaresInterface(ClassNode.java:946)
	at org.codehaus.groovy.ast.ClassNode.implementsInterface(ClassNode.java:926)
	at org.codehaus.groovy.ast.ClassNode.isDerivedFromGroovyObject(ClassNode.java:916)
	at org.codehaus.groovy.classgen.AsmClassGenerator.isGroovyObject(AsmClassGenerator.java:1070)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitPropertyExpression(AsmClassGenerator.java:1027)
	at org.codehaus.groovy.ast.expr.PropertyExpression.visit(PropertyExpression.java:55)
	at org.codehaus.groovy.classgen.asm.BinaryExpressionHelper.evaluateEqual(BinaryExpressionHelper.java:287)
	at org.codehaus.groovy.classgen.asm.BinaryExpressionHelper.eval(BinaryExpressionHelper.java:76)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitBinaryExpression(AsmClassGenerator.java:519)
	at org.codehaus.groovy.ast.expr.BinaryExpression.visit(BinaryExpression.java:49)
	at org.codehaus.groovy.classgen.asm.StatementWriter.writeExpressionStatement(StatementWriter.java:599)
	at org.codehaus.groovy.classgen.asm.OptimizingStatementWriter.writeExpressionStatement(OptimizingStatementWriter.java:354)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitExpressionStatement(AsmClassGenerator.java:501)
	at org.codehaus.groovy.ast.stmt.ExpressionStatement.visit(ExpressionStatement.java:40)
	at org.codehaus.groovy.classgen.asm.StatementWriter.writeBlockStatement(StatementWriter.java:80)
	at org.codehaus.groovy.classgen.asm.OptimizingStatementWriter.writeBlockStatement(OptimizingStatementWriter.java:155)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitBlockStatement(AsmClassGenerator.java:447)
	at org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:69)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClassCodeContainer(ClassCodeVisitorSupport.java:101)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitConstructorOrMethod(ClassCodeVisitorSupport.java:112)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitStdMethod(AsmClassGenerator.java:312)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitConstructorOrMethod(AsmClassGenerator.java:269)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitMethod(ClassCodeVisitorSupport.java:123)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitMethod(AsmClassGenerator.java:389)
	at org.codehaus.groovy.ast.ClassNode.visitContents(ClassNode.java:1056)
	at org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClass(ClassCodeVisitorSupport.java:50)
	at org.codehaus.groovy.classgen.AsmClassGenerator.visitClass(AsmClassGenerator.java:173)
	at org.codehaus.groovy.control.CompilationUnit$14.call(CompilationUnit.java:767)
	at org.codehaus.groovy.control.CompilationUnit.applyToPrimaryClassNodes(CompilationUnit.java:967)
	at org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:546)
	at org.codehaus.groovy.control.CompilationUnit.processPhaseOperations(CompilationUnit.java:524)
	at org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:501)
	at groovy.lang.GroovyClassLoader.doParseClass(GroovyClassLoader.java:306)
	at groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:287)
	at groovy.lang.GroovyShell.parseClass(GroovyShell.java:731)
	at groovy.lang.GroovyShell.parse(GroovyShell.java:743)
	at groovy.lang.GroovyShell.evaluate(GroovyShell.java:578)
	at hudson.init.impl.GroovyInitScript.execute(GroovyInitScript.java:83)
	at hudson.init.impl.GroovyInitScript.execute(GroovyInitScript.java:78)
	at hudson.init.impl.GroovyInitScript.init(GroovyInitScript.java:57)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at hudson.init.InitializerFinder.invoke(InitializerFinder.java:120)
	at hudson.init.InitializerFinder$TaskImpl.run(InitializerFinder.java:184)
	at org.jvnet.hudson.reactor.Reactor.runTask(Reactor.java:259)
	at jenkins.model.Jenkins$7.runTask(Jenkins.java:889)
	at org.jvnet.hudson.reactor.Reactor$2.run(Reactor.java:187)
	at org.jvnet.hudson.reactor.Reactor$Node.run(Reactor.java:94)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)

ComputerLauncherTest failed with LANG=ja_JP. 

Root cause of class loading error (on jnr.ffi.util.ref.internal.Finalizer$ShutDown) still unclear,
but easy fix is to simplify ClientAuthenticationCache.save to use FilePath.chmod,
which at least for now relies on hudson.util.jna.GNUCLibrary rather than JNR.

[FIXED JENKINS-19135] Permit a user to configure an axis with no values without throwing exceptions.
The project cannot be usefully built in this case but at least they can go back and reconfigure it.
Also fixing Layouter.Column to not throw NoSuchElementException (in violation of Iterator contract)
and thus break project overview when there is an empty Axis in the trivial list (due to an unintentional IndexOutOfBoundsException).

[JENKINS-17332] Allow sign up with username that exists because of SCM commit.