This article gives a brief overview of a number of key design concepts underlying the onedb service: * Architecture Overview * Core Data Model * Realms * Core Operations * Client Sessions * Synchronization For an introduction to onedb and the motivation for this service, please check the article "Introducing onedb: Connect Small Data in
Think about getting the persistence back-end of your next web app right ... sharding, replication, mapping, partitioning, consistency, latency, indices, durability, atomicity, isolation ... any terms familiar? Familar maybe, but certainly not pleasant. Modern database systems (e.g. RDMBS/Object DB/Graph DB) are easily one of the most complex aspects of
The Problem You would like to be able to create UNIX directories with numerical names, which increase incrementally, for instance: 0000 0001 0002 0003 etc. The Solution Just execute the following bash script in a directory, which contains at least the subdirectory '0000'. The script will create a
Given we have a script test.sh, it is easy to run this script in the background while continuing to work in the current shell session. The most cited way is by adding '&' to the end of the command: ./test.sh & However, this approach has one
Java's non-blocking IO (NIO) is a complex, yet amazingly powerful addition to Java to build scalable and performant network applications. The capabilities of Java NIO are particularly impressive if compared with alternative ways in the JRE to connect to web resources over http. Here is a small collection
Problem StackOverflowExceptions in Java and in other programming languages can be notoriously difficult to debug. The most troublesome attribute of these exceptions is that they occur in no specific place in the application. In specific, the location (class+line number) in which the exception is thrown does only point indirectly
Problem When wrapping an existing DOM element with a GWT widget (e.g. Button.wrap(…), HTML.wrap(…), etc), the GWT module will not load and report the exception like the following: java.lang.AssertionError: A widget that has an existing parent widget may not be added to the detach list
Problem While the GWT application works fine in development mode, it reports a mysterious NumberFormatException exception in production mode upon deserialization of an RPC on the server side. java.lang.NumberFormatException: Expected type 'int' but received an out-of-range value: -43400113595222000 at [..]ServerSerializationStreamReader.getNumberFormatException(ServerSerializationStreamReader.java:839) Analysis Apparently
Since some time now, Amazon offers a free (for 1 year) Micro Instance in their cloud for new sign ups. Micro instances are widely discussed as easy and relatively cheap way to run a cloud-based application (e.g. website/blog). Below a collection of a number of links regarding Amazon&
GWT RPC is a technology with both great promises as well as many practical pitfalls. On the one hand, GWT RPC magically handles the transport of objects from a Java server to a JavaScript based client, without any need to create and maintain legacy data formats (e.g. in JSON)
The world is rife for a new dominant programming language! Actually, has been rife for a couple of years, which, however, does not stop Java and C++ from dominating the screens of many unfortunate developers. Apart from the inarguably impressive features offered by 'new' languages, such as Scala,
One common theme in discussions of persistence is to be critical of the traditional SQL databases, which have been successfully used in business applications for decades. As alternative to these SQL databases, often so called NoSQL solutions are advocated. NoSQL, essentially, dramatically simplifies the kind of data, which can be