How To Write An Exception In Java

In the past few years, the innovative development of the open source world has elevated the productivity of Java™ developers to one level. Free tools, frameworks and solutions make up for once-scarce vacancies. The Apache CouchDB, which some people think is a WEB 2.0 database, is very promising. It's not difficult to master CouchDB, it's as simple as using a Web browser. This issue of Java open ...

This article series consists of two parts, and in part 1th of this series you will learn how to use the Tiyatien Center API and how to monitor deadlocks in a running Java application. Part 2nd uses the deadlock detection application developed in this article and adds a method to analyze the view to show where the application spends most of its CPU cycles. Have you ever encountered an application server hang without a clear cause or a Java application has become unresponsive? Is your application memory ...

Multithreading is the problem that programmers often face in the interview, the level of mastery and understanding of multithreading concept is often used to measure a person's programming strength. Yes, ordinary multithreading is not easy, then when multithreading encounter "elephants" will produce what kind of sparks? 　　Here we share the Java thread Pool management and distributed Hadoop scheduling framework with 严澜, the Shanghai Creative Technology director. Usually the development of the thread is a thing, such as Tomcat in the servlet is the threads, no thread how we provide more ...

I. Build HADOOP development environment The various code that we have written in our work is run in the server, and the HDFS operation code is no exception. During the development phase, we used eclipse under Windows as the development environment to access the HDFs running in the virtual machine. That is, accessing HDFs in remote Linux through Java code in local eclipse. To access the HDFS in the client computer using Java code from the host, you need to ensure the following: (1) Ensure host and client ...

Usually the development of the thread is a thing, such as Tomcat is a servlet in the threads, there is no thread how do we provide multi-user access? But many developers who have just started to touch threads have suffered a lot. 　　How to do a set of simple threading Development Mode framework for everyone from the single thread development into multithreaded development, this is really a relatively difficult project. What is the specific thread? First look at what the process is, the process is a system executed a program, this program can use memory, processor, file system and other related resources ...

In Java Web Development, it is often necessary to export a large amount of data to http://www.aliyun.com/zixun/aggregation/16544.html ">excel, using POI, JXL directly generate Excel, 　　It is easy to cause memory overflow. 　　1, there is a way, is to write data in CSV format file. 　　1 CSV file can be opened directly with Excel. 2 Write CSV file efficiency and write TXT file efficiency ...

Http://www.aliyun.com/zixun/aggregation/14223.html "> Application system, the log is an indispensable important part of all the application of error information should be able to find in the log file, 　　Some application system log may be very small, some large application system log is quite large, while the log file must be user-friendly and search, to have a high performance, otherwise it will affect the performance of the application system. Because the log usually involves I.

Often we want to delete some elements in the collection.　　Some might write that. public void operate (List list) {for (Iterator it = List.iterator (); It.hasnext ();)　　{String str = (string) it.next (); if (Str.equals ("Chengang")) {list ....

To use Hadoop, data consolidation is critical and hbase is widely used. In general, you need to transfer data from existing types of databases or data files to HBase for different scenario patterns. The common approach is to use the Put method in the HBase API, to use the HBase Bulk Load tool, and to use a custom mapreduce job. The book "HBase Administration Cookbook" has a detailed description of these three ways, by Imp ...

This paper is an excerpt from the book "The Authoritative Guide to Hadoop", published by Tsinghua University Press, which is the author of Tom White, the School of Data Science and engineering, East China Normal University. This book begins with the origins of Hadoop, and integrates theory and practice to introduce Hadoop as an ideal tool for high-performance processing of massive datasets. The book consists of 16 chapters, 3 appendices, covering topics including: Haddoop;mapreduce;hadoop Distributed file system; Hadoop I/O, MapReduce application Open ...