JDK 安装好了，之后 Sunspot 也安装好了，今天使用了一天可是晚上回来就不能用了（同一台机器），
scott@scott-ThinkPad-T420:~/work/dituhui$ java -version
java version "1.7.0"
Java(TM) SE Runtime Environment (build 1.7.0-b147)
Java HotSpot(TM) Server VM (build 21.0-b17, mixed mode)
scott@scott-ThinkPad-T420:~/work/dituhui$ javac -version
javac 1.7.0
执行：rake sunspot:solr:start（或者 bundle exec rake sunspot:solr:start）报错
scott@scott-ThinkPad-T420:~/work/dituhui$ rake sunspot:solr:start
java version "1.7.0"
Java(TM) SE Runtime Environment (build 1.7.0-b147)
Java HotSpot(TM) Server VM (build 21.0-b17, mixed mode)
rake aborted!
Server is already running with PID 0
Tasks: TOP => sunspot:solr:start
(See full trace by running task with --trace)
重启电脑也不行，总说 Server is already running with PID 0
有谁遇到过吗？怎么解决的？
是说服务正在运行，可以先结束在启动，rake sunspot:solr:stop 实在不行就把项目目录下的 solr/pids 下的文件删除， 当 sunspot 启动时，会判断这个 Pid 文件是否存在，如果存在就不能启动， 所以，需要先停止，再删除这个 pid 文件，应该就可以了
#1 楼 @saberma 报一堆错误。
scott@scott-ThinkPad-T420:~/work/dituhui$ rake sunspot:solr:start --trace
** Invoke sunspot:solr:start (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute sunspot:solr:start
java version "1.7.0"
Java(TM) SE Runtime Environment (build 1.7.0-b147)
Java HotSpot(TM) Server VM (build 21.0-b17, mixed mode)
rake aborted!
Server is already running with PID 0
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/sunspot_solr-1.3.1/lib/sunspot/solr/server.rb:62:in start'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/sunspot_solr-1.3.1/lib/sunspot/solr/tasks.rb:12:inblock (3 levels) in '
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/task.rb:205:in call'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/task.rb:205:inblock in execute'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/task.rb:200:in each'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/task.rb:200:inexecute'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/task.rb:158:in block in invoke_with_call_chain'
/home/scott/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/monitor.rb:211:inmon_synchronize'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/task.rb:151:in invoke_with_call_chain'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/task.rb:144:ininvoke'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/application.rb:116:in invoke_task'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/application.rb:94:inblock (2 levels) in top_level'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/application.rb:94:in each'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/application.rb:94:inblock in top_level'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/application.rb:133:in standard_exception_handling'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/application.rb:88:intop_level'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/application.rb:66:in block in run'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/application.rb:133:instandard_exception_handling'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/lib/rake/application.rb:63:in run'
/home/scott/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2/bin/rake:33:in'
/home/scott/.rvm/gems/ruby-1.9.3-p0/bin/rake:19:in load'
/home/scott/.rvm/gems/ruby-1.9.3-p0/bin/rake:19:in