terminology

Currently I'm reading "Java concurrency in practice", which contains this sentence: Since the action of a thread accessing a stateless object can't affect the correctness of operations on other threads, stateless objects are thread-safe. So, what is stateless object? Stateless object is an instance of a class without instance fields (instance variables). The class may have fields, but they are compile-time constants (static final). A very much related term is immutable . Immutable objects may have state, but it does not change when a method is invoked (method invocations do not assign new

There are two types of iterators in Java: fail-safe and fail-fast. What does this mean, and is the difference between them? Stephen C What is the difference between them ... "Fail safe" means: it won't fail. Strictly speaking, there is no such thing in Java as a fail-safe iterator. The correct term is "weakly consistent". The javadoc says: "Most concurrent Collection implementations (including most Queues) also differ from the usual java.util conventions in that their Iterators and Spliterators provide weakly consistent rather than fast-fail traversal." Typically, weak consistency means that

What is a coroutine? How are they related to concurrency? Coroutines and concurrency are largely orthogonal. Coroutines are a general control structure whereby flow control is cooperatively passed between two different routines without returning. The 'yield' statement in Python is a good example. It creates a coroutine. When the 'yield ' is encountered the current state of the function is saved and control is returned to the calling function. The calling function can then transfer execution back to the yielding function and its state will be restored to the point where the 'yield' was

I often see people saying that certain software is "very opinionated" or that Microsoft tends to write "un-opinionated" frameworks. What does this actually mean? If a framework is opinionated, it lock or guides you into their way of doing things. For example: some people believe that a template system shouldn't provide access to user defined methods and functions as it leaves the system open to returning raw HTML. So an opinionated framework developer only allows access to data structures. By design, the software is limiting and encourages the designer into doing things their way. Another

This question already has an answer here: What is the difference between a Docker image and a container? 21 answers What's the difference between a container and an image in Docker? In the Get started with Docker tutorial these terms are both used, but I do not understand the difference. Can anybody please shed some light? Images are frozen immutable snapshots of live containers. Containers are running (or stopped) instances of some image. Start with the base image called 'ubuntu'. Let's run bash interactively within the ubuntu image and create a file. We'll use the -i and -t flags to give us

What is the difference between the kernel space and the user space? Do kernel space, kernel threads, kernel processes and kernel stack mean the same thing? Also, why do we need this differentiation? Jerry Coffin The really simplified answer is that the kernel runs in kernel space, and normal programs run in user space. User space is basically a form of sand-boxing -- it restricts user programs so they can't mess with memory (and other resources) owned by other programs or by the OS kernel. This limits (but usually doesn't entirely eliminate) their ability to do bad things like crashing the

I have heard about things like "C Runtime", "Visual C++ 2008 Runtime", ".NET Common Language Runtime", etc. What is " runtime " exactly? What is it made of? How does it interact with my code? Or maybe more precisely, how is my code controlled by it? When coding assembly language on Linux, I could use the INT instruction to make the system call. So, is the runtime nothing but a bunch of pre-fabricated functions that wrap the low level function into more abstract and high level functions? But doesn't this seem more like the definition for the library, not for the runtime? Are "runtime" and "