chenyujin999-优快云博客

原创 shell 十三问：

shell 十三问：1) 为何叫做 shell？ 2) shell prompt(PS1) 与 Carriage Return(CR)的关系？ 3) 别人 echo、你也 echo，是问 echo 知多少？ 4) " "(双引号)与 ' '(单引号)差在哪？ 5) var=value？export前后差在哪？6) exec

2013-11-17 21:46:21 971

原创 How to find second highest or maximum salary of Employee in SQL - Interview question

Employee is one of the most frequently asked SQLinterview question similar tofinding duplicate records in table and when to use truncate vs delete. There are many ways to find second highest s

2013-11-17 21:44:51 1166

原创 Difference between save vs persist and saveOrUpdate in Hibernate

Save vs saveOrUpdate vs persist in HibernateWhat is difference between save and saveOrUpdate or Difference between save and persist are commoninterview question in any Hibernate interview, much li

2013-11-17 21:44:40 1159

原创 Why String is immutable or final in Java

This is one of the most popularString Interview questions in Java, which starts with discussion of, What is String, How String in Java is different than String in C and C++, and then shifted tow

2013-11-17 21:44:31 914

原创 Top 10 Struts Interview Question And Answer - J2EE

This time its Struts interview questions, After writingSpring interview questions few weeks back I was thinking what to pick for my interview series and than I thought about any web framework, a

2013-11-17 21:44:29 1498

原创 Top 10 Collection Interview Questions Answers in Java

Interview questions from Collection package or framework is most common in any Core Java Interview yet a tricky one. Together Collection and multithreading makes any Java interview tough to crack an

2013-11-17 21:44:17 2561

原创 Top 10 Java Serialization Interview Questions and Answers

What is Serialization in JavaJava Serialization is one of important concept but it’s been rarely used as persistencesolution and developer mostly overlooked Java serialization API. As per my exper

2013-11-17 21:44:07 1171

原创 How to create Immutable Class and Object in Java - Tutorial Example

Writing or creating immutable classes in Java is becoming popular day by day, because of concurrency and multithreading advantage provided by immutable objects. Immutable objects offers several bene

2013-11-17 21:43:55 1317

原创 Difference between Stack and Heap memory in Java

Difference between stack and heap memory is common programming question asked bybeginnerslearningJava or any other programming language. Stack and heap memory are two terms programmers starts hear

2013-11-17 21:43:44 1220

原创 What is the difference between Enumeration and Iterator ?

What are differences between Enumeration and Iterator This question is from early ages ofinterview , I have not seen this question on recentinterviews but it was common during 2006-2007 , now days

2013-11-17 21:43:40 1065

原创 How to use ConcurrentHashMap in Java - Example Tutorial and Working

ConcurrentHashMap in Java is introduced as an alternative of Hashtable in Java 1.5 as part of Java concurrencypackage. Prior to Java 1.5 if you need aMap implementation, which can be safely used

2013-11-17 21:43:33 1561

原创 Java String Replace Example Tutorial

This String replace example in Java will show you how to replace String in Java both at character level and by using regular expression.Since String is final in Java every time you replace Strin

2013-11-17 21:43:30 1048

原创 How to use Comparator and Comparable in Java? With example

Comparator and Comparable in Java ExamplesDifference between Comparator and Comparable in Java is very popular Java interview question mostly asked in telephonic round and writing code to sort obj

2013-11-17 21:43:22 1239

原创 String comparison is a common programming task and Java provides several way to compare two String i

String comparison is a common programming task andJava provides several way tocompare two String in Java. String is a special class in Java, String is immutable and It’s used a lot in every si

2013-11-17 21:43:07 1245

原创 Difference between transient and volatile keyword in Java

Surprisingly "Difference between transient and volatile keyword in Java" has asked many times onvarious java interview. volatile and transient are two completely different keywords from differen

2013-11-17 21:42:35 1084

原创 Difference between RegularEnumSet and JumboEnumSet in Java

Difference between RegularEnumSet and JumboEnumSet in Java was asked in a recent Java interview to one ofmy friend, unfortunately he hasn't explored this topic well and couldn't answer this question

2013-11-17 21:42:16 1083

原创 How to Iterate over Array in Java 1.5 using foreach loop Example

Though there are many ways to loop over Array in Java, including classical for loop, while loop with length counter, nothing matches elegance of Java 1.5 foreach loop, which makesiteration super e

2013-11-17 21:42:04 1364

原创 Hashtable and HashMap are two hash based collection in Java and used to store objects as key value p

Hashtable and HashMap are two hash based collection in Java and used to store objects as key value pair. Despite being hash based and similar in functionality there are significant difference betwee

2013-11-17 21:41:52 955

原创 Difference between ConcurrentHashMap and Collections.synchronizedMap and Hashtable in Java

AddthisJavarevisitedBlog about my experience in Java programming, SQL, UNIX, Interview questions, FIX Protocol, Tibco RV, JavaScript, jQuery, Equity trading technologies, SQL, XM

2013-11-17 21:33:12 1092

原创 Difference between ConcurrentHashMap and Collections.synchronizedMap and Hashtable in Java

Collections classes are heart of java API though I feel using them judiciously is an art. Its my personal experience where I haveimproved performance by using ArrayList where legacy codes are unne

2013-11-16 13:43:52 1237

原创 How to override compareTo method in Java - Example Tutorial

compareTo in Java is in the same league ofequals() and hashcode() and used to implementnatural order of object, compareTo is slightly different to compare() method of Comparator interface wh

2013-11-16 13:43:13 1243

原创 How to convert ArrayList to Set in Java with Example

Converting ArrayList to Setin Javameans creating a Set implementation like HashSet from an ArrayListfullof objects.Before Converting yourArrayList into hashSet do remember thatList keep insert

2013-11-16 13:42:35 1262

原创 Difference between Truncate and Delete command in SQL - Interview Questions with Example

Delete and truncate command in SQLTruncate and delete in SQL are two commands which is used to remove or delete data from table. Though quite basic in nature both sql commands can create lot of trou

2013-11-16 13:41:48 1297

原创 How SubString method works in Java - Memory Leak Fixed in JDK 1.7

Substring method from String classis one of most used method inJava, and it's also part of an interestingString interview question e.g. How substring works in Java or sometime asked as how does

2013-11-16 13:41:33 1230

原创 Difference between throw and throws in Exception handling - Java Example

Difference between throw and throwskeyword on Exception handling inJava is apopular core java interview question. Exception handling being an important part of Java programming language,comp

2013-11-16 13:40:48 1159

原创 Difference between List and Set in Java Collection

What is difference between List and Set in Java is a very popular Java collection interview questions and an important fundamental concept to remember while usingCollections class in Java. Both Li

2013-11-16 13:39:47 922

原创 Difference between DOM and SAX Parsers in Java

Difference between SAX and DOM Parser is very popularJava interview and often asked when interviewed on Java and XML. Both DOM and SAX parser are extensively used toread and parse XML file in

2013-11-16 13:39:39 1008

原创 How to create and execute JAR file in Java – Command line Eclipse Netbeans

Creating JAR file in java from command prompt is always been little tricky for many of us even if IDE like Netbeans andEclipse provide support to export java program as JAR file simply because w

2013-11-16 13:39:25 2551

原创 How to Parse or Read XML File in Java >> XML Tutorial Example

How to parse xml file in Java or how to read xml file in java is one of common need of a Java Developer working with enterprise Java application which uses XML for data representation, messaging and

2013-11-16 13:39:00 1487

原创 Step By Step guide to Read XML file in Java Using SAX Parser Example

Reading XML file in java using SAX Parser is little different thanreading xml file in Java with DOM parser which we had discussed in last article of this series. Thistutorial is can be useful fo

2013-11-16 13:38:40 1120

原创 How to Create and Evaluate XPath Expression in Java - Tutorial and Example

You can use XPathExpression from javax.xml.xpath package to create and execute XPATH expression inJava.Java API provides javax.xml.xpath package, which contains classes like Xpath, XpathFactory to

2013-11-16 13:37:32 1543

原创 JDOM Example : Reading and Parsing XML with SAX parser in Java

XML parsing with JDOM parserJDOM is an open source library which allow XML parsing and reading in Java program. JDOM is designed by using Java programming technique and customized for Java program

2013-11-16 13:37:12 1168

原创 Can we Override Private Method in Java? Inner Class?

No, you cannot override private methods in Java, private methods are non virtual in Java and access differently than non-private one. Sincemethod overriding can only be done on derived class and p

2013-11-16 13:36:43 1227

原创 How Synchronization works in Java ? Example of synchronized Block and Method

In thisJava synchronization tutorialwe will learn what is meaning of Synchronization in Java, Why do we need Synchronization in Java, What is java synchronizedkeyword, examples of usingJava synchr

2013-11-16 13:36:29 1564

原创 Difference between TreeMap and TreeSet in Java

Main Difference between TreeMap and TreeSet is that TreeMap is implementation of Map interface while TreeSet is implementation of Set interface. There are some similarities between both TreeMap and

2013-11-16 13:36:21 1044

原创 15 Java Enum Interview Questions for Developers with Answers

Enum was introduced in Java 5 and since then it's been very popular among Java developers and widely used in different Java applications. Since Enum in Java is much more versatile than Enum in C or C+

2013-11-16 13:34:53 1074

原创 10 Examples of HashMap in Java - Programming Tutorial

HashMap in Java is one of the most popular Collection class among Java programmers. After by articleHow HashMap works in Java, which describes theory part ofJava HashMap ,I thought to share, How

2013-11-16 13:33:59 1015

原创 Difference between Set, List and Map in Java - Interview question

Set, List and Map are three important interface of Java collection framework and Difference between Set, List and Map in Java is one of the most frequently askedJava Collection interview question.

2013-11-16 13:33:54 1131

原创 Thursday, August 16, 2012How to sort ArrayList in java - List Sorting - Ascending Descending Order

Sorting ArrayList in Java is not difficult, by using Collections.sort() method you cansort ArrayList in ascending and descending order in Java. Collections.sort() method optionally accept a Compar

2013-11-16 13:33:35 944

原创 Java Program to print Prime numbers in Java - Example Tutorial and Code

How to printPrime numbers in Java or how to check if a number is prime or not is classical Java programming questions, mostly taught in Java programming courses. A number is called prime num

2013-11-15 16:51:14 1477

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