Suraj Dubey surajdubey

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

	class ThreadSafeSingletonWithDoubleCheckedLocking {
	private static ThreadSafeSingletonWithDoubleCheckedLocking threadSafeSingleton;
	/**
	* private constructor so that other classes can't
	* instantiate it through constructor
	* any instantiation while creating new singleton instance should come here
	*/

	private ThreadSafeSingletonWithDoubleLocking() {}

	class ThreadSafeSingleton {

	private static ThreadSafeSingleton threadSafeSingleton;
	/**
	* private constructor so that other classes can't
	* instantiate it through constructor
	* any instantiation while creating new singleton instance should come here
	*/

	private ThreadSafeSingleton() {}

	class LazySingleton {
	// singleton instance
	private static LazySingleton lazySingleton = null;

	/**
	* private constructor so that other classes can't
	* instantiate it through constructor
	*/
	private LazySingleton() {
	// all initialization steps go here

	class EagerSingleton {
	private static EagerSingleton singletonInstance = new EagerSingleton();
	public static EagerSingleton getInstance() {
	return singletonInstance;
	}
	}

	sudo rm -fr /Library/Java/JavaVirtualMachines/jdk-9.jdk/
	sudo rm -fr /Library/Internet\ Plug-Ins/JavaAppletPlugin.plugin
	sudo rm -fr /Library/PreferencePanes/JavaControlPanel.prefPane