Most design patten books say we should “Favor object composition over class inheritance.” But can anyone give me an example that inheritance is better than object composition. Answer In Java, whenever you inherit from a class, your new class also automatically becomes a subtype of the original cla…
Tag: java
Android Socket + ObjectOutputStream not working correctly
I am developing a client/server program where the client is an android device. The server has a listener class that reads an object from the input stream. I created a client software for another COMPUTER that sends a small object over a local network. Computer to Computer works perfectly fine, i read the obje…
How project Lombok in java works and is that possible in .net using attributes?
Project Lombok makes it trivial to implement the boilerplate code in the classes. Is that possible with .NET attributes? Is any .net port there? Answer Well in Lombok a Java class might look like this While in C# the same class would look like this So C# (3.0 in this example) gets rather close without any oth…
commons beanutils alternative
I am looking for a commons beanutils alternative. The reason is that beanutils relies on commons-logging which is conflicting with existing libraries I am using. I would like a small self-contained alternative which will cause no/minimal conflicts. The main functionality I am after is nested property retrieva…
How to verify if a String in Java is a valid URL?
How to verify if a String in Java is a valid URL? Answer You can try to create a java.net.URL object out of it. If it is not a proper URL, a MalformedURLException will be thrown.
HowTo Unit Test Client Server Code
I’m currently writing a Java Client Server Application. So i want to implement two Libraries, one for the Client and one for the Server. The Client Server Communication has a very strict protocol, that I wan’t to test with JUnit. As build tool im using Maven and a Husdon Server for continues Integ…
nested Java collection to list items per person per day in a calendar grid using JSTL?
I am developing an employee scheduler Java web applicatyion where an employee can specify days they will be out of the office for things such as vacation, business travel, etc…I have a simple …
wait() and notify() method , always IllegalMonitorStateException is happen and tell me current Thread is not Owner Why?
Answer You need to hold the lock on the object you want to wait on (you can only call it within a synchronized block). Also, calling wait on a Thread is very unusual and probably not what you want. I am not sure what you are trying to do, but could you be confusing wait with sleep? If you want
Clone textview to append it to a ViewGroup
I have a ViewGroup defined in XML with a view inside, at onCreate time I’d like to have a variable of those. I don’t want to go through the hassle of using a listview+adapter cause its clearly overkill as I know the list won’t change since onCreate() This is more or less the code I’d l…
Java implementation of a… JVM?
Some time ago I found the MJVM project. Sadly, this project has been abandoned by it author (I asked Igor via email). I wonder if there is a (continued) open source project of a full implementation of a JVM in Java like this one. By “full”, I mean, not only to emulate mobile devices. Answer The Ji…