How to solve CommunicationsException in Java while using Hibernate and MySQL
You might have faced CommunicationsException, basically timeout issue in Java while connecting to MySQL using Hibernate. The session would be timed out after certain period of time. You might be thinking that the your site or application is running without any issue but it would have stopped or crashed due to below exception.
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 437,036,648 milliseconds ago. The last packet sent successfully to the server was 437,036,652 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem.
To solve this issue, create a file c3p0.properties and add the below properties. Place the file in the same path of Hibernate.cfg.xml. This file should be part of the jar.
c3p0.idleConnectionTestPeriod=100
c3p0.preferredTestQuery=SELECT 1
c3p0.testConnectionOnCheckin=true
c3p0.testConnectionOnCheckout=false
c3p0.debugUnreturnedConnectionStackTraces=true
com.mchange.v2.log.MLog=com.mchange.v2.log.log4j.Log4jMLog
Please post your feedback.
2888
comments powered by Disqus
Related Articles
Advantages and Disadvantages of using Hibernate like ORM libraries
Traditionally Programmers used ODBC, JDBC, ADO etc to access database. Developers need to write SQL queries, process the result set and convert the data in the form of objects (Data model). I think most programmers would typically write a function to convert the object to query and result set to object. To overcome these difficulties, ORM provides a mechanism to directly use objects and interact with the database.
How to learn from open source projects
Students ask this question frequently steps or methodology to learn from open source projects. There is no single answer or steps available. I listed the steps which i follow and i hope this will help for few.
Open source is the backbone for Startups
Many startups are entering in to the business due to open source. Open source acts as a back bone / pillar for their business. It reduces the cost of production, Generates revenue from consulting and support. This article describes about the startups which flourished because of open source. Sun acquired MySQL for $1Bn is the biggest achievement for open source startups.
An introduction to MongoDB
MongoDB is the most exciting SQL-free database currently available in the market. The new kid on the block, called MongoDB is a scalable, high-performance, open source, schema free and document oriented database that focuses on the ideas of NoSQL Approach. Written in C++, it has taken rapid strides since its emergence into the public sphere as a popular way to build your database applications.
Why require Searchengine? Why not use database for full text search in Enterprise application.
Most of the database has support of full text search, basically indexing and saarching. MySQL, Oracle and many more databases has in-built full text search. Then what is the need to go for external search engine like Lucene, Sphinx, Solr etc. Check out the advantage of using Searchengine.
Top 15 Open source alternative to Microsoft products
Microsoft is monopoly in the commercial software. Here are 15 best alternatives to most popular and widely used Microsoft products.
Pros and Cons of GPL licenese
GPL is widely used and known license in Open Source community. Richard Stallman father of GNU is the man behind GPL. GPL gives freedom and not free software.
Is Unix time end by 2038
In 32 bit operating system, Dates are calculated using number of seconds differece between 1 January 1970 and current date. This difference will reset to 00:00:00 on January 2038. This is called year-2038 Bug.
How hashmap works in Java. My style of learning.
This is the most frequently asked questions in the interview. Googling will throw many links related to this topic. How to learn the implementation of hash map? My style of learning using open source learning technique.
Lucene Vs Solr
Lucene is a search library built in Java. Solr is a web application built on top of Lucene. Certainly Solr = Lucene + Added features. Often there would a question, when to choose Solr and when to choose Lucene.
