5 ways to add multiple JAR in to Classpath in Java - Examples

How to add the JAR file to Classpath in Java

Adding JAR into classpath is a common task for Java programmers and different programmers do it in different ways. Since Java allows multiple ways to include JAR files in the classpath, it becomes important to know the pros and cons of each approach and How exactly they work. There are 5 ways to add jars into classpath in Java some of them we have already seen in  How classpath works in Java and How to set Path in Java. In this post, we will revisit some of those techniques and explore Java 1.6 wildcard to add multiple JAR into the classpath. 

Java Enum Tutorial: 10 Examples of Enum in Java

What is Enum in Java
Enum in Java is a keyword, a feature that is used to represent a fixed number of well-known values in Java, For example, Number of days in the Week, Number of planets in the Solar system, etc. Enumeration (Enum) in Java was introduced in JDK 1.5 and it is one of my favorite features of J2SE 5 among Autoboxing and unboxing, Generics, varargs, and static import. One of the common use of Enum which emerged in recent years is Using Enum to write Singleton in Java, which is by far the easiest way to implement Singleton and handles several issues related to thread-safety and Serialization automatically. 

What is @SuppressWarnings annotation in Java? Unchecked, RawTypes, Serial Example

@SuppressWarnings annotation is one of the three built-in annotations available in JDK and added alongside @Override and @Deprecated in Java 1.5. @SuppressWarnings instruct the compiler to ignore or suppress, specified compiler warning in annotated element and all program elements inside that element. For example, if a class is annotated to suppress a particular warning, then a warning generated in a method inside that class will also be separated. You might have seen @SuppressWarnings("unchecked") and @SuppressWarnings("serial"), two of most popular examples of @SuppressWarnings annotation. Former is used to suppress warning generated due to unchecked casting while the later warning is used to remind about adding SerialVersionUID in a Serializable class.

How to Code in Dart Programing language? Dart Hello World Example Tutorial

Google Datt is a general-purpose programming language from Google and is used to build web applications, mobile applications, and the Internet of Things (IoT).  Its most popular application is in Flutter framework, which is Google's mobile app SDK for crafting high-quality native interfaces on iOS and Android in record time. If you haven't tried it yet then it's a good time to try it and see how much it offers to a programmer and whether it is a suitable language to replace JavaScript or not. 

Inner class and nested Static Class in Java with Example

Inner class and nested static class in Java both are classes declared inside another class, known as top level class in Java. In Java terminology, If you declare a nested class static, it will called nested static class in Java while non-static nested classes are simply referred as Inner Class. Inner classes are also a popular topic in Java interviews. One of the popular questions is the difference between inner class and nested static class , some time also referred to as a difference between static and non static nested class in Java. One of the most important questions related to nested classes are Where should you use nested class in Java?

How to Attach Source Code in Eclipse to JAR Files for Debugging and Navigation With JDK Example

Attaching the source of any Jar in Eclipse e.g. JDK or open-source libraries like Spring framework is a good idea because it helps during debugging and code development. As a Java programmer at least you should attach the source of JDK in Eclipse IDE to find out more about JDK classes. Though Eclipse IDE is pretty good on code assist, sometimes You want to know what's going inside a library or a JDK method, rather than just reading the documentation. Interview questions like How HashMap works in Java or How substring causes memory leak can only be answered if you are familiar with the source code of these classes.  

How to add, subtract days, months, years, hours from Date and Time in Java - Example

Adding days, hours, month or years to dates is a common task in Java. java.util.Calendar can be used to perform Date and Time arithmetic in Java. Calendar class not only provides date manipulation but it also support time manipulation i.e. you can add, subtract hours, minutes and seconds from current time. Calendar class automatically handles date transition or month transition for example if you ask date after 30 days it will return you date based on whether current month is 30 or 31 days long. Same is true in case of adding and subtracting years, Calendar takes care whether current or following year is a leap year or not.

Difference between equals method and "==" operator in Java - Interview Question

Both equals() and "==" operators in Java are used to compare objects to check equality but the main difference between the equals method and the == operator is that the former is a method and the latter is an operator. Since Java doesn’t support operator overloading, == behaves identical for every object but equals() is a method, which can be overridden in Java, and logic to compare objects can be changed based upon business rules. Another notable difference between the == and equals method is that the former is used to compare both primitive and objects while the latter is only used for objects comparison.

What is final in Java? Final variable , Method and Class Example

Final in Java is very important keyword and can be applied to class, method, and variables in Java. In this java final tutorial we will see what is a final keyword in Java, what does it mean by making final variable, final method and final class in java and what are primary benefits of using final keywords in Java and finally some examples of final in Java. Final is often used along with static keyword in Java to make static final constant and you will see how final in Java can increase the performance of Java application.

How to get current date, month, year and day of week in Java program - Example tutorial

Here is a quick Java tip to get the current date, month, year, and day of the week from the Java program. Java provides a rich Date and Time API though having thread-safety issue but it's rich in function and if used locally can give you all the date and time information that you need for your enterprise Java application. In the last Java tutorial on Date and Time API we have seen how to get the current date and time from different timezone using DateFormat and SimpleDateFormat classes and in this post, we will get some more details like the current month, year, day of the week, etc by using java.util.Calendar class.  Just keep in mind that the Calendar instance should not be shared between multiple threads.

How to convert milliseconds to Date in Java - Tutorial example

Do you want to convert milliseconds to Date in Java? Actually java.util.Date is internally specified in milliseconds from epoch. So any date is the number of milliseconds passed since January 1, 1970, 00:00:00 GMT and Date provides constructor which can be used to create Date from milliseconds. Knowing the fact that Date is internally maintained in milliseconds allows you to store date in form of milliseconds in Server or in your Class because that can be effectively expressed with a long value.

Difference between mvn install, release and deploy commands in Maven - Examples

Even though there are a couple of powerful build and deployment tools that exist for Java applications like Gradle or ANT, It seems Maven is the king of them. I have used it in several Java projects over the years and it was initially ANT, but now they all use Maven with few Scala projects using Gradle. When you work with Maven you know that there are lots of commands to remember, especially if you are working on the command line. The thee Maven build commands which often confuses Java developers are mvn install, mvn release, and mvn deploy.

How to use instanceof operator in Java with example

The instanceof operator in Java is used to check if an object belongs to a particular type or not at runtime. It's also a built-in keyword in Java programming language and is mostly used to avoid ClassCastException in Java. It is used as a safety check before casting any object into a certain type. This operator has a form of object instanceof Type and returns true if the object satisfies IS-A relationship with the Type i.e. object is an instance of class Type or object is the instance of a class which extends Type or object is an instance of a class which implements interface Type.

How to remove duplicates elements from ArrayList in Java - Example

You can remove duplicates or repeated elements from ArrayList in Java by converting ArrayList into HashSet in Java. but before doing that just keep in mind that the set doesn't preserver insertion order which is guaranteed by List, in fact, that’s the main difference between List and Set in Java. So when you convert ArrayList to HashSet all duplicates elements will be removed but the insertion order will be lost. Let’s see this in action by writing a Java program to remove duplicates from ArrayList in Java.

How to read input from command line in Java using Scanner - Example

Java 5 introduced a nice utility called java.util.Scanner is capable of reading input from the command line in Java. Using Scanner is a nice and clean way of retrieving user input from the console or command line. The scanner can accept InputStream, Reader, or simply the path of the file from where to read input. In order to read from the command line, we can pass System.in into Scanner's constructor as a source of input. The scanner offers several benefits over the classical BufferedReader approach, here are some of the benefits of using java.util.Scanner for reading input from the command line in Java: