ArrayList vs Vector in Java - Interview Question

ArrayList vs Vector in Java
ArrayList and Vector is two most widely used Collection class in Java and used to store object in ordered fashion. Every Java programmer which is introduced to Java Collection Framework either started with Vector or ArrayList. For beginners Difference between Vector and ArrayList in Java  and LinkedList vs ArrayList are two most  popular Java Interview question. ArrayList vs Vector is not only important on interview perspective but also on effective use of Java Collection API. After reading this article you will know when to use Vector in Java, When to use ArrayList in Java and would be able to compare ArrayList vs Vector over several important parameters e.g. Speed, Synchronization, Code quality etc. Before seeing difference on Vector vs ArrayList, let's What is common between the.

Java String Matches Example - Regular Expression Tutorial

String Matching Example in Java
String matches method in Java can be used to test String against regular expression in Java. String matches() method is one of the most convenient ways of checking if String matches a regular expression in Java or not. Quite often we need to write code that needs to check if String is numeric, Does String contains alphabets e.g. A to Z or a to Z, How to check if String contains a particular digit 6 times, etc. There are so many cases in Java programming where we need a regular expression. If you are familiar with Java's regular expression API than you must know about java.util.regex.Pattern and java.util.regex.Matcher class, these class provides regular expression capability to Java API.

What is difference between Overloading and Overriding in Java

Overloading vs Overriding in Java
In last couple of articles we have seen What is method overloading and What is method overriding in Java and now we will see What is difference between overloading and overriding in Java. Overloading vs overriding is one of those frequently asked Java interview question which can not be ignored. Overloading vs Overriding has appeared in almost every Java interview, mostly at beginner and intermediate level e.g. 2 to 4 years experience. In fact most of those tricky Java interview Question came from Overloading and Overriding. It's one of the tricky fundamental to understand. In this article we will some important difference between Overloading and Overriding which not only help to understand concept better but also serves as good recap for Java interviews.

Top 10 Java Web Service Interview question answers

Java Web Services Questions and Answers
Web Services interview questions are part of J2EE interviews for jobs which are looking some experience in Java web services Space. Most of the Web services questions come from two different way of implementing Web Services e.g. SOAP and REST. SOAP is an standard and mature way of calling Web Services which uses XML while REST is a new way of implementing Web Services which is based on HTTP protocol. In fact REST Web Service interview questions are getting more and more popular on web services interviews in Java, So if you are going for any Java J2EE interview which require some web service experience, be prepare with both SOAP and REST Web services questions.

keytool command examples Java - add view ssl certificate in keyStore trustStore

The keytool command in Java is a tool for managing certificates into keyStore and trustStore which is used to store certificates and requires during SSL handshake process. By using keytool command you can do many things but some of the most common operation is viewing certificate stored in keystore, importing new certificates into keyStore, delete any certificate from keystore etc. For those who are not familiar keyStore, trustStore and SSL Setup for Java application , Here is a brief overview on What is a trustStore and keyStore in Java. Both trustStore and keyStrore is used to store certificate signed by signer authority or CA (Certificate authority), with keyStore additionally storing personal certificate for client which is used during client authentication on SSL handshake process if its enable.

Difference between ServletConfig and ServletContext in JSP Servlet J2EE

Difference between ServletConfig and ServletContext

ServletContext and ServletConfig these two are important interface of Servlet API which is used by Java J2EE programmer during web application development. Correct understanding of What is ServletContext and ServletConfig is very important for any J2EE application developer. Apart from that Difference between ServletContext and ServletConfig are a popular Servlet JSP interview questions and mostly asked on both fresher and experienced Java programmer during J2EE interviews. Both ServletContext and ServletConfig are basically configuration objects which are used by servlet container to initialize various parameter of web application. But they have some difference in terms of scope and availability so first we see what is ServletContext and ServletConfig objects are and then we will see difference between ServletConfig and ServletContext in Java J2EE.

Rules of Method Overloading and Overriding in Java

The overloading and overriding rule in JavaSince you can either overload or override methods in Java, its important to know what are the rules of overloading and overriding in Java. any overloaded method or overridden method must follow rules of method overloading and method overriding to avoid compile-time error and logical runtime errors;  where you intend to override a method but method get overloaded. That is not uncommon and happens several times when Java programmer tries to override equals in Java or overriding compareTo method in Java while implementing Comparable interface, which accepts Object type of argument. From Java 5 onwards which introduces @Override annotation along with Enum, Generics, and varargs method you can completely avoid that problem.

Top 10 Tough Core Java Interview Questions Answers for Programmers

tough core Java interviews questions and answers
What is a tough core java interview question? Why do people look for tough Java questions before going for an interview? well, I don't think I need to answer these tough questions because it's pretty natural to prepare for tough questions even if you are not expecting tough questions from core Java. If you are prepared for the tough and tricky Java interview question then you feel more confident and answer other Java interview questions with confidence. On the other hand, if you are not prepared for tough and tricky core Java questions than seeing them on Java interview or written test may surprise you. But the definition of tough core Java questions is not universal, the same Java question which is easy for one programmer might be tough for other Java programmers.

Palindrome: Java program to check number is palindrome or not

How to find if a number is a palindrome in Java

Checking whether a number is palindrome or not is a classical Java homework exercise. When you start learning Java programming most institute which teaches Java programming provides these classical Java programs like How to find Armstrong number in Java or how to find the Fibonacci number in Java using recursion etc. Write a Java program to check if the number is palindrome comes from the same category. For those who are not familiar with palindrome numbers, a palindrome number is a number which is equal to reverse of itself. For example, 121 is a palindrome because the reverse of 121 is 121, while 123 is not a palindrome in Java because the reverse of 123 is 321 and 121!=321. Finding a palindrome number is easy in Java, you just need to develop logic to reverse a number in Java.