leonzhx
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心存高远：
谢谢作者分享，刚好看到这里不太明白，现在茅塞顿开。不过runt ...
关于 Maven的传递依赖的理解 -
sxlkk：
851228082 写道甚至在某次技术会议现场遇到《Maven ...
关于 Maven的传递依赖的理解 -
851228082：
851228082 写道a----compile----b-- ...
第五章 坐标和依赖 -
851228082：
a----compile----b-----provided- ...
第五章 坐标和依赖 -
851228082：
甚至在某次技术会议现场遇到《Maven in action》的 ...
关于 Maven的传递依赖的理解
文章列表
1. Thread groups were originally envisioned as a mechanism for isolating applets for security purposes. They never really fulfilled this promise, and their security importance has waned to the extent that they aren’t even mentioned in the standard work on the Java security model.
2. Thread gro ...
1. The best way to write a robust, responsive, portable program is to ensure that the average number of runnable threads is not significantly greater than the number of processors. This leaves the thread scheduler with little choice: it simply runs the runnable threads till they’re no longer runnab ...
1. As is the case for most optimizations, the best advice for lazy initialization is “don’t do it unless you need to”.
2. If a field is accessed only on a fraction of the instances of a class and it is costly to initialize the field, then lazy initialization may be worthwhile. The only way to ...
1. In normal operation, Javadoc does not include the synchronized modifier in its output, and with good reason. The presence of the synchronized modifier in a method declaration is an implementation detail, not a part of its exported API. It does not reliably indicate that a method is thread-safe. ...
1. Given the difficulty of using wait and notify correctly, you should use the higher-level concurrency utilities instead. The higher-level utilities in java.util.concurrent fall into three categories: the Executor Framework, concurrent collections and synchronizers.
2. The concurrent collecti ...
1. java.util.concurrent contains an Executor Framework, which is a flexible interface-based task execution facility. Creating a work queue requires a single line of code:
ExecutorService executor = Executors.newSingleThreadExecutor();
Here is how to submit a runnable for execution:
e ...
1. To avoid liveness and safety failures, never cede control to the client within a synchronized method or block. In other words, inside a synchronized region, do not invoke a method that is designed to be overridden, or one provided by a client in the form of a function object. The class has no kn ...
1. Without synchronization, one thread’s changes might not be visible to other threads. Not only does synchronization prevent a thread from observing an object in an inconsistent state, but it ensures that each thread entering a synchronized method or block sees the effects of all previous modifica ...
1. An empty catch block defeats the purpose of exceptions, which is to force you to handle exceptional conditions. At the very least, the catch block should contain a comment explaining why it is appropriate to ignore the exception.
2. An example of the sort of situation where it might be appr ...
1. Generally speaking, a failed method invocation should leave the object in the state that it was in prior to the invocation. A method with this property is said to be failure atomic.
2. The simplest way to achieve failure atomicity is to design immutable objects. If an operation fails, it ma ...
1. When a program fails due to an uncaught exception, the system automatically prints out the exception’s stack trace. The stack trace contains the exception’s string representation, the result of invoking its toString method. This typically consists of the exception’s class name followed by its de ...
1. Always declare checked exceptions individually, and document precisely the conditions under which each one is thrown using the Javadoc @throws tag.
2. Don’t take the shortcut of declaring that a method throws some superclass of multiple exception classes that it can throw.
3. While th ...
1. Higher layers should catch lower-level exceptions and, in their place, throw exceptions that can be explained in terms of the higher-level abstraction. This idiom is known as exception translation.
2. A special form of exception translation called exception chaining is appropriate in cases ...
1. Reusing preexisting exceptions has several benefits. Chief among these, it
makes your API easier to learn and use because it matches established conventions with which programmers are already familiar. A close second is that programs using your API are easier to read because they aren’t clutte ...
1. Unlike return codes, the checked exceptions force the programmer to deal with exceptional conditions, greatly enhancing reliability.
2. An unchecked exception is more appropriate unless the exceptional condition cannot be prevented by proper use of the API and the programmer using the API ...