public String filterForeMostClassPath(String classPath, Logger logger) {
		List<String> classPathList = new ArrayList<>();
		for (String eachClassPath : checkNotNull(classPath).split(File.pathSeparator)) {
			String filename = FilenameUtils.getName(eachClassPath);
			if (isForemostJar(filename) || isUsefulForForemostReferenceProject(eachClassPath)) {
				logger.trace("classpath :" + eachClassPath);
				classPathList.add(eachClassPath);
			}
		}
		return StringUtils.join(classPathList, File.pathSeparator);
	}
Construct the classpath of ngrinder which is very important and located in the head of
classpath.

@param classPath classpath string
@param logger    logger
@return classpath optimized for grinder.
ngrinder-core/src/main/java/net/grinder/util/AbstractGrinderClassPathProcessor.java