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Java Keywords (Part XXIV): native

Java keyword list abstract continue for new switch assert default goto * package synchronized boolean do if private this break double implements protected throw byte else import public throws case enum instanceof return transient catch extends int short try char final interface static void class finally long strictfp volatile const * float native super while Keyword marked with an asterisk (*) are keywords that, although valid, are not used by programmers. This is the last chapter of the Java Keyword series. This is probably the keyword I have used the least. In my 20 year career as a software developer, I have used this keyword once, and that was to make some addition to legacy code. The keyword native is a method modifier . Basically, it is a keyword that can only be applied to methods. According to the Java Language Specification (JLS), A method that is native is implemented i...

Exception Handling: File CRUD Operations Example

Introduction to Exception Handling This is a supplement to my previous blog Creating Custom Exception Classes in Java . I recommend you read that one first and then read this one. Java provides many Exception (and Error) Handling classes. Both of these categories implement the Throwable interface. Although it is not imperative that you develop your own custom exception classes, it is often a good idea to do so; particularly when dealing with large systems. The main reason to create custom exception classes is to quickly identify which custom class is being affected or causing these custom exceptions. For example, referencing a null object and trying to use it will result in a NullPointerException . However, in your code, there could be literally hundreds or even thousands of statements which could result in such exception. Designing your Custom Exception Class Suppose that you are designing a class that will serve as a message receiver. For simplicity, ...

Creating Custom Exception Classes in Java

Introduction My first piece of advice: Search the web. There is a ton of information that is available to you on the Internet. However, beware where you go for information. There are many places with bad information as well. For this topic, the safest source of information is the Oracle The Java Exceptions Tutorials . Starting with the basics, the first thing to do is determine whether or not you need the custom exception class to begin with. We are going to assume we need to handle an exception that it is not clearly represented already in Java. To create a custom exception class, we must use a name that it is meaningful. Typically, the exception class is named after a process or a class name that will throw the exception. For instance, if I create a MessageReceiver class that could result in an exception, I might consider naming my exception class MessageReceiverException. The UML diagram below depicts this relationship between the class and the custom ...