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Closed 9 years ago.
We have a Java EE application that support Oracle, MySQL and SQL Server vendors.
we are using a view model to view the fetched data from DB, also using pagination in the DAO model, and that's working good so far, but now we are working with millions of records like 10 millions, that cause to us a big problem since our application performance issues become very bad. After some investigations we had make we found that the order by in the query cause a big slowness in the DB level, but we still have to use it.
The question is : is there any technique to work with this amount of data with a good performance (response time and memory issues) ?
If you use ORDER BY clause frequently you should create an index on field your are ordering by. It would dramatically increase ordering performance (but of course will slightly slow down insertion).
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Closed 10 years ago.
We use Oracle ADF platform to build web applications and extend to webcenter portal application.
The current expectation from Java developers team is to change our development approach/method, so that adding some fields in the application should not required any development effort. In other words, when you want to add a data field (at least no relation to any field) in some form, it should be enough to save some metadata of the field to the database along with execution of related job/commands in the application. Additionally, we need to render the view dynamically according to added fields.
Essentially, I think that such an expectation is not suited for the Java world, but if it could be possible or if someone has prior experience to do this, I would want to use it. We don't want to be interact directly with the database using native SQL through JDBC, as that would mean going out of the ADF framework.
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Closed 10 years ago.
I was asked this questions in one interview.
Suppose there is a requirement of highly concurrent application e.g. Email application like Gmail where in
say there 100K users accessing the application at the same time.
You are allowed to ask only 3 questions to client which 3 questions will you ask?
Client in this case is company who want the application to get developed. e.g.Google [Disclaimer: Name is
just to give idea. I know what you must be thinking :) ]
I was really confused there can be n number of questions starting with technology, hardware configuration etc. Can some one tell me which can be best suited questions in above case.
SLAs (expected uptime, response times, usage patterns, etc.)
How much can be spent on maintenance (servers/cloud, support)
Expected growth
Budget?
Desired delivery date?
Do you have a pen to sign or will you need one?
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Closed 10 years ago.
what is the best DataBase for a mobile java program ? J2ME
Used DB file outside of .jar file of program
best speed in running query
have more SQL propertise Like Curser, trigger and ...
needed low space (under 1 Mb)
Other things that is needed for run a high speed java program on every mobile device that have a little amount of space and low speed prossesor.
I fear this question has no real answer. There are loads of databases you could use and none of us know the problem nearly well enough to give you a solid answer on this issue. There are countless SQL and NoSQL options for storing data. Off the top of my head, I would recommend looking at mobile-nosql and perhaps this thread.
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Closed 10 years ago.
Our current system is based on a Spring/Hibernate/Java/MySQL stack. We have a relationship with a company for which we will end up doing a portion of the IT work. They are currently building a system using an outside vendor which is based on PHP/MySQL. I would like to make an argument that they should reconsider and switch to a Java-centric platform. My main argument is that we can utilize our current (Java-based) skillset for system maintenance and enhancements, instead of having a system which requires knowledge of both PHP and Java. However, they have asked if there is any technical reason why this couldn't happen.
It would be great if I could bring some technical arguments to table which show the two platforms are incompatible. However, I've googled the differences, and as far as I can tell, there wouldn't be any particular technical issues. For example, we could use web services for the systems to communicate.
So, the question is, is there anything one could say about PHP which makes it either incompatible with or just not as "good" as Java? E.g security, scalability and other enterprise considerations? I know it's a vague question, but it would be very helpful to get some input.
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Closed 11 years ago.
I thought that hibernate is the most used Java ORM, by far. Is its usage declining? If so, where are people migrating to?
You are looking at search trends, not usage trends
A lot of people know Hibernate sufficiently for their daily needs, so they don't search as much for it. I expect this to be the dominant effect. Compare it for example with log4j which declines as well but certainly is still heavily used (and no the decline can't be explained with slf4j) http://www.google.com/trends?q=log4j%2C+slf4j
As mentioned above a lot of people are talking (searching) JPA although they might use Hibernate as the implementation.
Some people realized that maybe the whole ORM thing is a bad idea ... but that probably doesn't show significantly in the search trends
My guess would be it's JPA (of which Hibernate is also a provider). Because of this alias (which wasn't available in 2005) the declining trend for Hibernate may be misleading: some of the growing JPA uses are backed by the "declining" Hibernate, offsetting or even reversing the decline.