jruby-1.6.4 :006 > fs.create_writer('/var/log/metlog*')
Java::JavaLang::NullPointerException:
	from org.jruby.util.CodegenUtils.human(CodegenUtils.java:98)
	from org.jruby.util.CodegenUtils.prettyParams(CodegenUtils.java:152)
	from org.jruby.java.dispatch.CallableSelector.argumentError(CallableSelector.java:462)
	from org.jruby.java.dispatch.CallableSelector.argTypesDoNotMatch(CallableSelector.java:436)
	from org.jruby.java.invokers.RubyToJavaInvoker.findCallable(RubyToJavaInvoker.java:191)
	from org.jruby.java.invokers.StaticMethodInvoker.call(StaticMethodInvoker.java:26)
	from org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:282)
	from org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:71)
	from org.jruby.ast.CallManyArgsNode.interpret(CallManyArgsNode.java:59)
	from org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
	from org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
	from org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:75)
	from org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:190)
	from org.jruby.internal.runtime.methods.DefaultMethod.call(DefaultMethod.java:179)
	from org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:312)
	from org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:169)
... 130 levels...
	from org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:75)
	from org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:190)
	from org.jruby.internal.runtime.methods.DefaultMethod.call(DefaultMethod.java:179)
	from org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:312)
	from org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:169)
	from Users.victorng.$_dot_rvm.rubies.jruby_minus_1_dot_6_dot_4.bin.irb.__file__(/Users/victorng/.rvm/rubies/jruby-1.6.4/bin/irb:17)
	from Users.victorng.$_dot_rvm.rubies.jruby_minus_1_dot_6_dot_4.bin.irb.load(/Users/victorng/.rvm/rubies/jruby-1.6.4/bin/irb)
	from org.jruby.Ruby.runScript(Ruby.java:679)
	from org.jruby.Ruby.runScript(Ruby.java:672)
	from org.jruby.Ruby.runNormally(Ruby.java:579)
	from org.jruby.Ruby.runFromMain(Ruby.java:428)
	from org.jruby.Main.doRunFromMain(Main.java:278)
	from org.jruby.Main.internalRun(Main.java:198)
	from org.jruby.Main.run(Main.java:164)
	from org.jruby.Main.run(Main.java:148)
	from org.jruby.Main.main(Main.java:128)jruby-1.6.4 :007 >