Checked & Unchecked Exceptions

|

Checked Exceptions
  • are subclasses of java.lang.Exception
  • need to be declared in a method or constructor's throws clause
Unchecked Exceptions
  • are subclasses of java.lang.RuntimeException
  • do not need to be declared in a method or constructor's throws clause

In the context of common transaction APIs, such as JTA or Spring transaction APIs;
any RuntimeException triggers rollback, and any checked Exception does not rollback the transaction.


Runtime
Rollback
Unchecked

Yorumlar

Yorum Gönder

Popular

Servlet

|
In Java EE world, Servlet simply is a web technology with which we can receive and handle the HTTP requests, create HTTP response and return that response back to the client. Servlet technology makes a basis for other Java web technologies on top of which other frameworks put their extensions. For example JSP, JSF, Spring MVC are such technologies which are uses Servlet technology at behind.  Servlets run on a web container such as Tomcat which provides the services on Java EE technology stack .  What is a servlet ? Servlet simply makes an object having HTTP-server functionality when its class extends HttpServlet class. A servlet is mapped to a URL to which clients request HTTP requests made to the URL is directed to the corresponding Servlet object Servlet implementation receives the request in the form of GET, POST, PUT or DELETE Servlet implementation runs a business logic and prepares an HTTP response and sends it back to the client just an HTTP server does Lif...
Devamı

Java 14 New Features

|
Java SE 14 was released in March 2020. The full list of new features in JDK 14 can be found here: https://openjdk.org/projects/jdk/14/   In this tutorial, we will look over some of these new features and examine some of them. 1. JEP 305: Pattern Matching for instanceof (Preview) With this JEP, instanceof now allows casting of the checked object to a variable. Before Java 14: if (obj instanceof String) { String s = (String) obj; // use s } With Java 14: if (obj instanceof String s) { // can use s here } else { // can't use s here } 2. JEP 345: NUMA-Aware Memory Allocation for G1 This JEP i mproves G1 performance on large machines by implementing NUMA-aware( non-uniform memory access ) memory allocation. Use the  +XX:+UseNUMA option to enable it. 3. JEP 358: Helpful NullPointerExceptions This JEP  improves the usability of  NullPointerException  generated by the JVM by describing precisely which variable was  null . Let's look over the follo...
Devamı

Proxy Server

|
Resim
There are two kinds of proxy servers; forward proxy and reverse proxy. Forward Proxy A forward proxy is also known as proxy server or web proxy. Proxy servers are located in front of clients and provides managed access to outside of the internal network. In a typical scenerio; A client wants to access a website on the internet and makes a request over proxy. Why doesnot the client access directly ? Because the client is prevented direct connection to the internet for security concerns. The proxy executes some logic on the request decides whether to forward or not. The proxy forwards the request to where it's routed. The server to which the request is sent does not know about the client, it knows the proxy as the sender. The server responds back to the proxy. And the proxy route the response to the client. Use cases Enforcing security policies on clients in the internal network. Blocking access to certain websites. A blocked-ip-ranged client for a websi...
Devamı