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Can we overload static method in Java Program - Example

Overloading static method In Java
Yes, we can overload static method in Java. In terms of method overloading static method is just like normal methods and in order to overload the static method you need to provide another static method with the same name but different method signature. Static overloaded method is resolved using Static Binding during compile time. Overloading method in Java is completely different than the overriding method and as discussed in the last article we can not override static method in Java but we can certainly overload a static method in Java. Here is an example which confirms that we can overload static method in Java:

Can we override private method in Java - Example program

No, We can not override private method in Java, just like we can not override static method in Java. Like static methods, private method in Java is also bonded during compile time using static binding by Type information and doesn't depends on what kind of object a particular reference variable is holding. Since method overriding works on dynamic binding, its not possible to override private method in Java. private methods are not even visible to Child class, they are only visible and accessible in the class on which they are declared. private keyword provides highest level of Encapsulation in Java. Though you can hide private method in Java by declaring another private method with same name and different method signature.

Difference between String and StringBuffer in Java

String vs StringBuffer in Java
String and StringBuffer are two classes which are most widely used in any Java program. If I say you can not write a program without using String in Java then it would not be an exaggeration. The string is everywhere, the main method accepts String argument, logs are String etc. Though many Java programmers familiar with String, not many are careful while performing operations on String, Since String is final in Java; every operation e.g. converting String into Uppercase, creating SubString,  converting String to Lowercase all result in a separate new String Object, which can take trigger frequent garbage collection and affect your application performance. here comes StringBuffer in Java which is a mutable version of String, though it's not as feature rich as String and you can not use StringBuffer in place of String but StringBuffer should be used whenever you are performing String concatenation instead of String in Java.

What is class file in Java - How to create Class File

What is class file in Java
Class file in Java is compiled form of Java source file. When we compile Java program which is written in Java source file  ended with .java extension, it produces one more class files depending upon how many classes are declared and defined in that Java source file. One Java source file can only contain one public class and its name must match with name of file e.g. HelloWorld.java file can contain a public class whose name should be HelloWorld as shown below :

What is transient variable in Java - Serialization Example

What is transient variable in Java
transient variable in Java is a variable whose value is not serialized during Serialization and which is initialized by its default value during de-serialization, for example for object transient variable it would be null. this behavior can be customized by using Custom Serialized form or by using Externalizable interface. transient variable is used to prevent any object from being serialized and you can make any variable transient by using transient keyword. By the way difference between transient and volatile variable in Java is a famous Java interview question but transient variable is completely different than volatile variable which we have discussed in our post What is volatile variable in Java.

Difference between HashSet and HashMap in Java

HashSet and HashMap in Java
HashSet vs HashMap is a classical Java Collection interview question which focuses on What are differences between HashSet and HashMap in terms of features, usage, and performance. If you are in Java programming even for a year or so, you are likely to be familiar with What is HashSet in Java and What is HashMap in Java, these two are most popular collection classes. Despite being hash based collection HashSet and HashMap are different to each other because the underlying interface is different. HashSet implements Set interface via extending AbstractSetclass and HashMap implements Map interface. Before seeing differences between let's see what is common between HashSet and HashMap in Java:

5 difference between Hashtable and HashMap in Java

Hashtable vs HashMap in Java
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 a significant difference between Hashtable and HashMap and without understanding those difference if you use Hashtable in place of HashMap than you may run into series of subtle programs which is hard to find and debug.Unlike Difference between ArrayList and HashMap,  Difference between Hashtable and HashMap are more subtle because both are similar kind of collection. Before seeing difference between HashMap and Hashtable let's see some common things between HashMap and Hashtable in Java.

Top 10 Java Programming Coding Interview Questions Answers for programmers

Java coding interview questions answers
Java coding interview questions are mostly some programming exercises which is asked to be solved in java programming language in limited time during any core Java or J2EE interview. No matter whether you have 2 years of experience or 4 years of experience, There is always some coding interview question in Java programming job you are applying. Actually questions related to Java Coding are increasingly getting popular on Java interviews for two reasons, first its difficult to crack Java coding interview questions than answering fact based questions like Why String is immutable in Java or Why main is static in Java; Second reason of popularity of Coding question in Java interviews is read need of good developers who are required to do lot of coding in projects rather than doing some maintenance works.

10 Advanced core Java interview questions for senior and experienced programmer

Java interview questions for Senior and Experienced programmer
Java is very big and there is no way to prepare completely for any core java interview but there is a level of question depends upon your experience, if you are fresher than questions asked in Java interview are mostly based on fundamentals like Iterator vs Enumeration in Java, Why main is public static and void or may be ArrayList vs LinkedList in Java. Things changes when you apply for senior developer, Technical lead or Team Lead Java positions, questions asked on that level are more advanced and less popular among Java circles, you may be asked questions from design pattern, questions from multi-threading, Collections and even asked to write code, design classes and prepare JUnit tests. In this Java article I will share some advanced Core Java interview questions which is appear in Senior level interviews mostly on 4 to 6 years and 6 to 8 years of experience. One important thing to note is that you can not clear interview by just mugging answers of these question because interviewer is most likely asked you follow-up question based upon your response and only way to get through it is to understand the topic well.

What is PATH and CLASSPATH in Java - Path vs ClassPath

What is PATH and CLASSPATH in Java
The PATH and CLASSPATH are two most important environment variables of Java environment which is used to find the JDK binaries used to compile and run Java in windows and Linux and class files which are compiled Java bytecodes. From my personal experience I can say that PATH and CLASSPATH are two most problematic thing for beginners in Java programming language due to two reasons; first because in most of Java courses nobody tell details of what is a PATH and CLASSPATH, What do PATH and CLASSPATH do, What is meaning of setting PATH and CLASSPATH, What happens if we do not set them, Difference between PATH vs CLASSPATH in Java or simply How Classpath works in Java etc. These basic question which answers most of the details about PATH and CLASSPATH in Java are mostly not answered until Java programmer itself acquire these knowledge, Things may be changed nowadays but important of PATH and CLASSPATH is still high. Most common cause of dreaded error like java.lang.NoClassDefFoundError and java.lang.ClassNotFoundException is either incorrect or misconfigured CLASSPATH in Java.

What is main method in Java ? Why main is public static and void

What is main method in Java
main method in Java is an standard method which is used by JVM to start execution of any Java program. main method is referred as entry point of Java application which is true in case of core java application but in case of container managed environment like Servlet, EJB or MIDlet this is not true as these Java programs have there own life-cycle methods like init(), service() or destory() for Servlet's which is used by container. main method in Java is run by main thread which is a non daemon thread and Java program runs until main method finishes or any other user thread is running. When we start JVM by running java command we also provide name of class which contains main method, which is later invoked by JVM to start Java program execution. for example in below command :

How to determine if a string has all unique characters in Java?

This is one of the common string-based coding problems from programming job interviews. You need to write a program to determine if a given string has all unique characters or not. For example input= "Java" then your function should return false because all characters are not unique, and if the input is "Python" then your program should return true because all characters in Python are unique. For the purpose of this problem, you can assume the given String only contains ASCII printable characters, though you should always verify that with the interviewer.