what is profiling in java

type modifier (typespecifier). It is designed to modify variables that are visited and changed by different threads. Variables defined by the volatile type are extracted directly from the corresponding memory each time the system uses it, rather than using the cache. After using the volatile modifier member variable, the values of the variables that all threads see at any time are the same. A demo sample using volatile

synchronization method than a mutex The acquisition of the lock in the critical section is called entering the critical zone; And the release of the lock is called leaving the critical section. Differences (with semaphores and mutexes) Mutexes and semaphores are visible in any process of the system; In other words, a process creates a mutex or semaphore, and another process attempts to acquire the lock

be type-detected, or the array itself is holding the object, and the generic container is only in the compiler to check type safety, and in the run time is all object, only half-definition, or the generic container does not hold objects, it will lead to the above problems.Summary: In this chapter we mainly compare arrays with generic containers and observe

Click to enter _ more _java FAQ-base Class Library1, Java.math package has what functionThe Java.math package provides a mathematical class in Java. Includes basic floating-point libraries, complex operations, and arbitrary-precision data operations. Main classes such as:?The classes in math are described below: arbitrary length shapingBigInteger, the arbitrary length of the non-variable shaping. Beca

1.new can call a constructor with parameters, newinstance not.2.new is a Java keyword used to construct an instance of a class. Newinstance is a method of Class, but the same is true of the two notation.3.newInstance: Weak type. Low efficiency. Only parameterless constructs can be called. NEW: Strongly typed. relativel

Click to enter _ more _java thousand ask1, meta-annotation is whatSee the comments here: what is the commentUnderstanding custom Annotations See here: How to customize annotationsMeta annotations are responsible for annotating other annotations. Java 5 defines 4 standard meta-annotations (meta-annotation): @Target, @Re

Fooloader are actually used, this takes care of T He lazy instantiation , and is it guaranteed Thread safe. When you are also want to being able to serialize your object you need to make sure that deserialization won ' t create a copy. Public Final classFooImplementsSerializable {Private Static Final LongSerialversionuid = 1L; Private Static classFooloader {Private Static FinalFoo INSTANCE =NewFoo (); } PrivateFoo () {if(Fooloader.instance! =NULL

What is the difference between an abstract class and an interface?1, abstract class in the Java language is represented by an inheritance relationship, a subclass can inherit only one parent class, but may implement multiple interfaces.2, in an abstract class can have their own member variables and non-abstract class m

In the study of design patterns, found in the book has repeatedly referred to the commission of the word, so after the online search to get results, and wrote a small example. What is a delegate?The delegation mode is a basic technique in software design pattern. In delegate mode, there are two objects involved in processing the same request, and the object tha

+ ")"); }}When I put this problem to my yard friends to see, their first reaction is: Who TM write code, readability is too poor, requires refactoring.But when it comes to specific output, they're still a little skeptical.Yes, we are now a high-level route, for the basics of things, it is not necessarily grasp.The results are as follows:base1commonbase1last=====

Click to enter _ more _java thousand ask1. What is ATTACHAPI?The Attach API is a set of extension APIs provided by Sun, which is not a standard Java API. As the name implies, Attach, some programs are attached to the JVM. Simply put, a program