Author Archives: Jesper Udby

About Jesper Udby

I'm a freelance computer Geek living in Denmark with my wife and 3 kids. I've done professional software development since 1994 and JAVA development since 1998.

Salesforce wsc: upsert null fields

  The salesforce upsert() callĀ  is brilliant for interfacing legacy systems with Salesforce, especially if the data you are going to replicate into already contains some sort of unique identification. It will create records that does not exist, and update … Continue reading

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Salesforce wsc: ConnectionException should have been Fault

This is the first article where I discuss details or issues using wsc (JAVA) on an Oracle WebLogic platform to integrate Customer Legacy systems with Salesforce CRM. In some environments (specifically the WLS 10.3.5 used as production environment at my … Continue reading

Posted in Java, Salesforce | Tagged , , , , , | 2 Comments

usl4j – Ultra Simple Logging for JAVA

Back in the late 90’ties when I started programming JAVA there were no standard way of logging in JAVA programs. One usually just used System.out.println(), System.err.println() and Exception.printStacktrace(). Often applications would build homemade logging frameworks that would also log information … Continue reading

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Simple logarithm implementation in PIC assembler

Most natural observations are exponentational/logarithmic in nature. I often do simple hardware using Microchip PIC processors (usually 12F or 16F families). Hardware doing some business in the home. One such example is my Christmas-tree-lightning-controller. Basically it only turns my electric … Continue reading

Posted in Microcontoller, Open Source, Personal, PIC | Tagged , , | 4 Comments

Locking a row, portable between databases, with JDBC

A couple of years ago I was with a project designing a system to manage Investor Meetings. An Investor must have a valid Pass in order to join a Meeting. Each Pass has a unique serial number. It was a … Continue reading

Posted in Databases, Java | Tagged , , , , , | 1 Comment

Squareroot (sqrt) with BigDecimal

Recently I was refactoring some code from using double to using BigDecimal and suddenly needed a square root method. I remembered years ago I was taught a simple “successive approximation” method; believe it was grammar school. I searched the net … Continue reading

Posted in Java | Tagged , | 2 Comments

Implementing a simple database semaphore

In this article I will describe a simple technique that enables you to implement an “exclusive lock” in a distributed, even clustered, environment. The technique works with all major databases, and should work with any database that has a reasonable … Continue reading

Posted in Databases, Java | Tagged , , , , , , , , | 11 Comments

Financial (monetary) computations using floating point arithmetic [in JAVA]

In this article, I will discuss some of the issues in doing financial calculations in JAVA. The issues are not related to JAVA only, but to any calculation done in a “computer language” using binary floating point arithmetic, including calculations … Continue reading

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Securing J[2]EE applications, part 3

In this third article, the samples are modified to be run on JBoss (4.0.3+) and JavaDB (Derby version 10.2). The first article showed how to setup Glassfish authentication with only a single database table. The second article evovled the simple … Continue reading

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Securing J[2]EE applications, part 2

The first part, Securing J[2]EE applications, part 1, discusses a simple setup where a single database table, 2 views and a correctly configured jdbcRealm could handle the most basic authentication and authorization requirements. This second article discusses a few enhancements … Continue reading

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