Java

Features: 1. The function name is the same as the class name. 2, do not define the return value type. 3, there is no specific return value. P.S. Adding the return value before the constructor is just a generic function. Function: Initializes an

Source url:http://www.cnblogs.com/peida/archive/2013/04/24/3036689.html the meaning of the annotation: Annotation (annotation) is Java provides a way and method of associating any information with any metadata (metadata) in the elements of a

record some of the good pen questions you've encountered 1, The following Java program outputs the result to ___. int i=0; Integer j = new Integer (0); System.out.println (i==j); System.out.println (J.equals (i)); Answer: TRUE parsing:The subject

1,file class Represents the name of a particular file and the name of a group of files under a directory. If it points to a set of files, you can call the list () method with the collection of words and return an array of characters. Example

Reference: https://www.jianshu.com/p/1716ce690637http://ifeve.com/talk-concurrency-countdownlatch/ What's countdownlatch? Countdownlatch is also called latching, which is introduced in JDK1.5, allowing one or more threads to wait for another

Program counter: A line number indicator that can be viewed as the byte code executed by the current thread, and in the conceptual model of the virtual machine, the bytecode interpreter works by changing the value of the counter to select the next

1. Concurrent Programming Concepts of Atomic An operation cannot be split again, that is, an operation or multiple operations are either fully executed and the process of execution is not interrupted by any factor or executed. A classic example is

Zookeeper provides authority authentication as zookeeper client access restrictions, there are two main ways, 1, IP mode 2, digest permission mode You can define permission content by creating a node. Here is the Java implementation Package

Recently in doing an amateur project, expect to learn the Java language in the project, encountered in the process of bytebuffer, feeling in this project is a very important foundation of a thing, so take this opportunity to learn, to

The difference between the Equals method in Java and the "= =": The Equals method is the Java.lang.Object class method. There are two ways to use these instructions: (1) For string variables, the comparison method differs when comparing strings

First of all, the Java API has provided a one-way list of classes, you can use directly. The purpose of this realization is to better understand the data structure of the linked list. This is mainly to introduce some common structure inside the use

The error occurred, I collected are:1, do not have this field2, use the collection storage, and directly with the collection call, namely: (Collection. Field name)3, with the label, did not write a label, directly on the collection name, callThe

Java comparison time differs by several months Do project today encounter data returning 6 months from the current month CompareTo method of new characteristic yearmonth of scheme 1::java1.8 Compare the same year, such as the current August 2017,

Title: Move a number of the first elements of an array to the end of the array, which we call rotation. Enter a rotation of an ascending sorted array, outputting the smallest element of the rotated array. For example, the array {3,4,5,1,2} is a

Java Draw mathematical function diagram is not very convenient, need to use a third party package jfree, installation or download methods online. To use the xyseries inside the Jfree, generate a series of data. Then, based on the generated data, use

Transferred from https://my.oschina.net/fhd/blog/289945 Examples are as follows: Package test; public class Gen { private T ob; Public Gen (T o) { ob = O; Public T Getob () {return ob; Public void ShowType () { System.out.println (' Type ' T is ' +

1. Generics are a new feature of Java 1.5, the essence of which is a parameterized type, which means that the data type being manipulated is specified as a parameter. This type of parameter can be used in the creation of classes, interfaces, and

Sometimes in spring, a class marks a lot of annotations. In fact, Java annotations can be inherited (that is, merging multiple annotations into 1) such as Springmvc's notes. @RestController @RequestMapping ("/person") Can be merged into

DirectoryWhat is a reentrant lock and why do I need to be able to reentrant the lock with a reentrant lock? Demo Code Show reference article 1. What is a reentrant lock The concept of a lock is not to be explained more, when a thread A is already

When ActiveMQ uses the IBM JDK, the logging.properties file cannot be found when started with Bin/activemq.bat, but it can also be started. Failed to start when registering as Windows system service: FATAL | wrapper | 2013/04/27 09:56:05 |