private void appendToBootstrapClassLoaderSearch() {
        // DCL
        if (injectedToRoot) {
            return;
        }
        synchronized (lock) {
            if (this.injectedToRoot == false) {
                instrumentEngine.appendToBootstrapClassPath(pluginConfig.getPluginJarFile());
                // Memory visibility WARNING
                // Reordering is not recommended.
                this.injectedToRoot = true;
            }
        }
    }
@author Woonduk Kang(emeroad)
@author jaehong.kim
agent-module/profiler/src/main/java/com/navercorp/pinpoint/profiler/instrument/classloading/BootstrapClassLoaderHandler.java