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Displaying posts with tag: Java (reset)
Communications link failure MySQL JDBC with TLS

Ran into an interesting situation trying to configure a MySQL JDBC driver to connect over TLS (though the driver may call it SSL, TLS is the name for more recent versions of the protocol).

The error I was getting was pretty generic:

Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

With the relevant parts of the stacktrace, also being non helpful:

at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
        at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
        at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:835)
        at com.mysql.cj.jdbc.ConnectionImpl.(ConnectionImpl.java:455)
        at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)
        at …
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Java Thread Class Tutorial With Example | Java.lang.Thread Class

Java Thread Class Tutorial With Example | Java.lang.Thread Class is today’s topic. The java.lang.Thread class is a thread of execution in a program. The Java Virtual Machine allows an application to have multiple threads of execution running concurrently. The Thread class, along with its methods and the Runnable interface, builds the multithreading system in Java. Multithreading or Multithreaded programming is a concept in Java, and Computer Science in general, in which multiple threads can be executed simultaneously.

Java Thread Class

Following are the essential points about Thread in Java.

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SQL Triggers Tutorial With Example | Triggers in SQL

SQL Triggers Tutorial With Example | Triggers in SQL is today’s topic. SQL trigger is invoked by the database automatically when any change in the event occurs. It is known as a particular type of stored procedure because triggers are called directly, which is not done in case of stored procedures. The only difference between SQL triggers and stored procedures is that stored procedure needs to be called explicitly, whereas SQL triggers are called implicitly. SQL triggers are invoked when a row is inserted in a table, or any columns are being updated.

SQL Triggers Tutorial With Example

Triggers are the stored programs, which are automatically fired or executed when some events take place. It is like event-based programming. Triggers are written to be executed in the response to any of the …

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Why is My Java Application Freezing Under Heavy I/O Load?

The Question Recently, a customer asked us:

Why would heavy disk IO cause the Tungsten Manager and not MySQL to be starved of resources?

For example, we saw the following in the Manager log file tmsvc.log:

2019/06/03 00:50:30 | Pinging the JVM took 29 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 25 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 21 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 16 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 12 seconds to respond.
2019/06/03 00:50:30 | Pinging the JVM took 8 seconds to respond.

The Answer Why a Java application might be slow or freezing

The answer is that if a filesystem is busy being written to by another process, the background I/O will cause the Java JVM garbage collection (GC) to pause.

This problem is not specific to Continuent Tungsten …

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MySQL Connector/J 8.0.15 has been released

Dear MySQL users,

MySQL Connector/J Version 8.0.15 is the GA release of the 8.0
branch of MySQL Connector/J. It is suitable for use with MySQL Server
versions 8.0, 5.7, 5.6, and 5.5. It supports the Java Database
Connectivity (JDBC) 4.2 API, and implements the X DevAPI.

This release includes the following new features and changes, also
described in more detail on

https://dev.mysql.com/doc/relnotes/connector-j/8.0/en/news-8-0-15.html

As always, we recommend that you check the “CHANGES” file in the
download archive to be aware of changes in behavior that might affect
your application.

To download MySQL Connector/J 8.0.15 GA, see the “Generally Available
(GA) Releases” tab at …

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On MySQL XA Transactions

One of the features I missed in my blog post on problematic MySQL features back in July is XA transactions. Probably I was too much in a hurry, as this feature is known to be somewhat buggy, limited and not widely used outside of Java applications. My first related feature request, Bug #40445 - "Provide C functions library implementing X/OPEN XA interface for Bea Tuxedo", was created almost 10 years ago, based on the issue from one of MySQL/Sun customers of that time. I remember some …

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On Innovation. Interview with Scott McNealy

“We made it a point to hire really smart, visionary people and then let them do their work.
I wanted to delegate and let people be in charge of things. My own decision-making process was to decide who got to decide. To make decisions, you have to first outline the problem, and if you hire really great people, they’re going to know more about the problem they’re dealing with than you ever will.”–Scott McNealy

I have interviewed Scott McNealy. Scott is a Silicon Valley pioneer, most famous for co-founding Sun Microsystems in 1982. We talked about Innovation, AI, Big Data, Redis, Curriki and Wayin.

RVZ

Q1. You co-Founded Sun Microsystems in 1982, and served as CEO and Chairman of the Board for 22 years. What are the main lessons learned in all these years?

Scott …

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Does the Version Number Matter?

Yes, it does! In this blog post, I am going to share my recent experiences with ProxySQL and how important the database software version number can be.

Migration

I was working on a migration to Percona XtraDB Cluster (PXC) with ProxySQL, fortunately on a staging environment first so we could catch any issues (like this one).

We installed Percona XtraDB Cluster and ProxySQL on the staging environment and repointed the staging application to ProxySQL. At first, everything looked great. We were able to do some application tests and everything looked good. I advised the customer to do more testing to make sure everything works well. …

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Connector/J 8.0.11, the Face for Your Brand New Document-oriented Database

This is exciting news: MySQL 8.0 is officially GA!

This time around we do not only offer you a new MySQL Server full of exciting new features, but also a brand new toolset that let you make the most out of MySQL, including the now GA Java database driver, MySQL Connector/J 8.0.11!

This story is about Connector/J but before even I get started I must say a few words about the new features that conducted the development of this new driver. If you prefer, you can jump directly to the Connector/J 8.0 topic below.

What’s new in MySQL Server 8.0? There’s a new Client/Server communication protocol in MySQL: the X Protocol

The X Protocol introduced in MySQL 8.0 series is the backbone for the document-oriented paradigm in the MySQL ecosystem. The new X Protocol and the old MySQL Client/Server Protocol are both available …

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JDBC Driver Connection URL strings

Introduction Ever wanted to connect to a relational database using Java and didn’t know the URL connection string? Then, this article is surely going to help you from now on. Oracle The JDBC connection properties look as follows: JDBC Driver oracle.jdbc.OracleDriver JDBC Url jdbc:oracle:thin:@localhost:1521/orclpdb1 Hibernate Dialect org.hibernate.dialect.Oracle12cDialect And, if you want to connect using a … Continue reading JDBC Driver Connection URL strings →

The post JDBC Driver Connection URL strings appeared first on Vlad Mihalcea.

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