private File prepareClasspathFile(ILaunchConfiguration configuration,String classpath){
  return prepareConfigFile(configuration,classpath,".classpath");
}

private File prepareClasspathFile ( ILaunchConfiguration configuration , String classpath ) { return prepareConfigFile ( configuration , classpath , ".classpath" ) ; }
a private helper to prepare a classpath file to workspace metadata , we use this to prevent classpath too long which was caused the problem for reaching windows command length limitation .
