Tejas Lagvankar wrote a nice post about this subject. Below are some key differences between Service and IntentService. When to use? The Service can be used in tasks with no UI, but shouldn’t be too long. If you need to perform long tasks, you must use threads within Service. The IntentService can be used in … Read more
When I am having a big heated discussion at work, I use a rubber chicken which I keep in my desk for just such occasions. The person holding the chicken is the only person who is allowed to talk. If you don’t hold the chicken you cannot speak. You can only indicate that you want … Read more
A daemon thread is a thread that does not prevent the JVM from exiting when the program finishes but the thread is still running. An example for a daemon thread is the garbage collection. You can use the setDaemon(boolean) method to change the Thread daemon properties before the thread starts.
Needed background on concurrency approaches: Different web servers implement different techniques for handling incoming HTTP requests in parallel. A pretty popular technique is using threads — that is, the web server will create/dedicate a single thread for each incoming request. The Apache HTTP web server supports multiple models for handling requests, one of which (called … Read more
It is generally a bad pattern to kill a thread abruptly, in Python, and in any language. Think of the following cases: the thread is holding a critical resource that must be closed properly the thread has created several other threads that must be killed as well. The nice way of handling this, if you … Read more
One possible (and common) use is when you have some object that is not thread-safe, but you want to avoid synchronizing access to that object (I’m looking at you, SimpleDateFormat). Instead, give each thread its own instance of the object. For example: public class Foo { // SimpleDateFormat is not thread-safe, so give one to … Read more
Here are some pros/cons I came up with. Multiprocessing Pros Separate memory space Code is usually straightforward Takes advantage of multiple CPUs & cores Avoids GIL limitations for cPython Eliminates most needs for synchronization primitives unless if you use shared memory (instead, it’s more of a communication model for IPC) Child processes are interruptible/killable Python … Read more
The synchronized keyword is all about different threads reading and writing to the same variables, objects and resources. This is not a trivial topic in Java, but here is a quote from Sun: synchronized methods enable a simple strategy for preventing thread interference and memory consistency errors: if an object is visible to more than … Read more
You have to move the portion of the background task that updates the UI onto the main thread. There is a simple piece of code for this: runOnUiThread(new Runnable() { @Override public void run() { // Stuff that updates the UI } }); Documentation for Activity.runOnUiThread. Just nest this inside the method that is running … Read more
ServletContext When the servlet container (like Apache Tomcat) starts up, it will deploy and load all its web applications. When a web application is loaded, the servlet container creates the ServletContext once and keeps it in the server’s memory. The web app’s web.xml and all of included web-fragment.xml files is parsed, and each <servlet>, <filter> … Read more