Category Archives: Development

WebSockets with Grails

Last week I had an interesting discussion about how to relief a threaded application server’s burden. If clients regularly poll the application server with a certain time window, just to ask whether there are updated information available, every time a … Continue reading

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Java CSV-Parser Comparison on Github

There are quite a few Java CSV parsers available. If you are unsure which one to choose or you wonder how they perform, have a look at github. There is a project┬áto do performance testing of┬ávarious CSV parsers. If you … Continue reading

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How to install Groovy on a Banana Pi or Raspberry Pi

The Raspberry or Banana Pi have already pre-installed Python. If you like to stay with Groovy on these nice little devices, here are the instructions to install Groovy. GVM makes the whole process very easy and convenient. Open a terminal … Continue reading

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Posted in Development, Groovy | Tagged , , , , | 2 Comments

How to Solve: “Too many connections”; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException:

Hi, in one of my projects I used GPars and its withPool() method to execute some async tasks. The prime purpose of a task is to fetch some data from external sources and save the resulting data to a database. … Continue reading

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Create a WebCrawler with less than 100 Lines of Code

Hi, while you find excellent open source Web crawlers (e.g. crawler4j), I wanted to write a crawler with very little coding. Very often I use the famous Jsoup library. Jsoup has some nice features to find and extract data from … Continue reading

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Posted in Development, Groovy | Tagged | 2 Comments

How to solve: ** java.lang.instrument ASSERTION FAILED ***: “!errorOutstanding” with message transform method call failed at ../../../src/share/instrument/JPLISAgent.c line:

Hi, as I tested some memory intensive, recursive functions with GGTS 3.6 and Grails 2.4, execution was interrupted with the following error message: While this error message is not really helpful to find the root cause, I guess it has … Continue reading

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