why Jruby can't require 'net/http/server' and gnu.io.PortInUseException error

Question

I'm trying to run jruby application, but it fails with error:

LoadError: no such file to load -- net/http/server
  require at org/jruby/RubyKernel.java:1054
  require at ../jruby-1.7.4/lib/ruby/shared/rubygems/custom_require.rb:36
   (root) at lib/main.rb:4

What does it means? o_O

Some times, I see another error:

bmalets:trunk bmalets$ sh bin/qatcher.sh 
Experimental:  JNI_OnLoad called.
Stable Library
=========================================
Native lib Version = RXTX-2.1-7
Java lib Version   = RXTX-2.1-7
Connecting to serial port /dev/tty.usbmodemfa131
CommPortIdentifier.java:354:in `open': gnu.io.PortInUseException: Unknown Application
    from NativeMethodAccessorImpl.java:-2:in `invoke0'
    from NativeMethodAccessorImpl.java:39:in `invoke'
    from DelegatingMethodAccessorImpl.java:25:in `invoke'
    from Method.java:597:in `invoke'
    from JavaMethod.java:470:in `invokeDirectWithExceptionHandling'
    from JavaMethod.java:328:in `invokeDirect'
    from InstanceMethodInvoker.java:71:in `call'
    from CachingCallSite.java:346:in `cacheAndCall'
    from CachingCallSite.java:204:in `call'
    from CallTwoArgNode.java:59:in `interpret'
    from InstAsgnNode.java:95:in `interpret'
    from NewlineNode.java:105:in `interpret'
    from BlockNode.java:71:in `interpret'
    from ASTInterpreter.java:74:in `INTERPRET_METHOD'
    from InterpretedMethod.java:139:in `call'
    from DefaultMethod.java:170:in `call'
    from CachingCallSite.java:306:in `cacheAndCall'
    from CachingCallSite.java:136:in `call'
    from VCallNode.java:88:in `interpret'
    from NewlineNode.java:105:in `interpret'
    from BlockNode.java:71:in `interpret'
    from ASTInterpreter.java:74:in `INTERPRET_METHOD'
    from InterpretedMethod.java:204:in `call'
    from DefaultMethod.java:194:in `call'
    from CachingCallSite.java:336:in `cacheAndCall'
    from CachingCallSite.java:179:in `callBlock'
    from CachingCallSite.java:183:in `call'
    from RubyClass.java:855:in `newInstance'
    from RubyClass$INVOKER$i$newInstance.gen:-1:in `call'
    from JavaMethod.java:294:in `call'
    from CachingCallSite.java:326:in `cacheAndCall'
    from CachingCallSite.java:170:in `call'
    from CallOneArgNode.java:57:in `interpret'
    from InstAsgnNode.java:95:in `interpret'
    from NewlineNode.java:105:in `interpret'
    from BlockNode.java:71:in `interpret'
    from ASTInterpreter.java:74:in `INTERPRET_METHOD'
    from InterpretedMethod.java:204:in `call'
    from DefaultMethod.java:194:in `call'
    from CachingCallSite.java:336:in `cacheAndCall'
    from CachingCallSite.java:179:in `callBlock'
    from CachingCallSite.java:183:in `call'
    from RubyClass.java:855:in `newInstance'
    from RubyClass$INVOKER$i$newInstance.gen:-1:in `call'
    from JavaMethod.java:294:in `call'
    from CachingCallSite.java:326:in `cacheAndCall'
    from CachingCallSite.java:170:in `call'
    from lib/main.rb:37:in `chained_0_rescue_1$RUBY$SYNTHETIC__file__'
    from lib/main.rb:34:in `__file__'
    from lib/main.rb:-1:in `load'
    from Ruby.java:807:in `runScript'
    from Ruby.java:800:in `runScript'
    from Ruby.java:669:in `runNormally'
    from Ruby.java:518:in `runFromMain'
    from Main.java:390:in `doRunFromMain'
    from Main.java:279:in `internalRun'
    from Main.java:221:in `run'
    from Main.java:201:in `main'

P.S.:

ruby version:

• jruby 1.7.4 (1.9.3p392) 2013-05-16 2390d3b on Java HotSpot(TM) 64-Bit Server VM 1.6.0_65-

java version:

• java version "1.6.0_65"
• Java(TM) SE Runtime Environment (build 1.6.0_65-b14-462-11M4609)
• Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-462, mixed mode)

Answer 1

If cause of error:

CommPortIdentifier.java:354:in `open': gnu.io.PortInUseException: Unknown Application

just create and chmod /var/lock folder :)

mkdir /var/lock
chmod go+rwx /var/lock