java - eclipse project has to run twice to compile updates -

recently eclipse (version 3.8.1) started behave strange. assume i'm running particular java project , have hit run button run project , if modifications code , rerun it, output executed code. new updated code executed when i'm running project second time.

restarting eclipse won't resolve this. this won't happen if i'm debugging code.

edit: debugging found @ first run ignores debugging points , run code (the previous version). debugging have run debug twice if modification code.

i not sure help, me worked: window->preferences->run/debug->launching: in field "general options" check box in string "build (if required) before launching". when had same problem, box unchecked.