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About Me

Hello, I am Naresh Joshi and I welcome you to Java By Source. Java By Source is a friend to Java programming and Java related technologies and frameworks like Spring, Hibernate, Struts, Web Services, Micro Services, Design Patterns, Multithreading, Collection, XML, SQL.


I love to create my own thoughts about anything which comes to my notice and I think we should always have our own thinking on everything rather than just following what others think.

That’s why I have started writing this blog to keep all my research notes and my thoughts regarding Java programming language in one place and make them available to others.

Thanks for visiting Java By Source and I hope you enjoyed the posts. Any kind of feedback is always welcomed and appreciated. You can submit any query or suggestion in the Contact Us box (Bottom Right). You can also reach me on LinkedIn or Facebook or Github.

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Popular posts from this blog

Why an outer Java class can’t be static

In a previous blog , I talked about why we can not define an outer class using private or protected keywords. If you have not read it, please go ahead and give it a look. I this article I will talk what is the use of the static keyword, why an outer Java class can’t be static, why it is not allowed in Java to define a static outer class. In order to understand that first, we need to understand what is the static keyword used for, what purpose it solves and how does it works. What does static keyword do Every Java programmer knows that if we need to define some behavior (method) or state (field) which will be common to all objects we define it as static. Because static content (behavior or state) does not belong to any particular instance or object, it will common to all objects and all objects are free to change any static field and every change will be visible to every object. We do not need to create any object of the class to access a static field or method, we can directly...

Why Single Java Source File Can Not Have More Than One public class

According to Java standards and common practices we should declare every class in its own source file. And even if we declare multiple classes in the single source file (.java) still each class will have its own class file after compilation. But the fact is that we can declare more than one class in a single source file with below constraints, Each source file should contain only one public class and the name of that public class should be similar to the name of the source file. If you are declaring the main method in your source file then main should lie in that public class If there is no public class in the source file then main method can lie in any class and we can give any name to the source file. If you are not following 1st constraint then you will receive a compilation error saying “ The public type A must be defined in its own file ”.  While if you are not following the second constraint you will receive an error “ Error: Could not find or load main class User ” after ...

Creating objects through Reflection in Java with Example

In Java, we generally create objects using the new keyword or we use some DI framework e.g. Spring to create an object which internally use Java Reflection API to do so. In this Article, we are going to study the reflective ways to create objects. There are two methods present in Reflection API which we can use to create objects Class.newInstance() → Inside java.lang package Constructor.newInstance() → Inside java.lang.reflect package However there are total 5 ways create objects in Java, if you are not aware of them please go through this article 5 Different ways to create objects in Java with Example . Both Class.newInstance() and java.lang.reflect.Constructor.newInstance() are known as reflective methods because these two uses reflection API to create the object. Both are not static and we can call earlier one on a class level object while latter one needs constructor level object which we can get by using the class level object. Class.newInstance() The Class class is th...