以编程方式删除Eclipse环境变量插件开发

Question

我目前正在开发一个必须删除Eclipse Environment变量的插件，现在我有了这个：

public static void removeEnvironmentVariable(IProject proj, String variable) {
    // environment path
    ICProjectDescription prjDesc = CoreModel.getDefault().getProjectDescription(proj);  

    IEnvironmentVariableManager envManager = 
            CCorePlugin.getDefault().getBuildEnvironmentManager(); 
    IContributedEnvironment contribEnv = envManager.getContributedEnvironment(); 

    // We must iterate through all configurations 
    for(ICConfigurationDescription config : prjDesc.getConfigurations()) {
        contribEnv.removeVariable(variable, config);
    }

    // Save the changes to the environment 
    try {
        CoreModel.getDefault().setProjectDescription(proj, prjDesc);
    } catch (CoreException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

我做错了什么？