Checking data consistency – 2 – smartmontools

In order to ensure the consistency of a data storage, a regularly check is recommended. This might be checking a hdd, sdd, usb stick, flash card (sd,cf). In general there is only a basic check by the operating system. This check is insufficient to guarantee no data loss. When using Linux there are some small tools that provide an enhanced check for data consistency. This second part describes the usage of smartmontools. Continue reading

Comparing Serialization Performance

When transmitting data, all the information must be serialized. When Serializing there are two relevant criteria in order to select a suitable format: size and performance. This article compares the efficiency of different serialization formats (Java Serialization, ByteBuffer, Unsafe, Json and Protobuf). Continue reading

Checking data consistency – 1 – badblocks

In order to ensure the consistency of a data storage a regularly check is recommended. This might be checking a hdd, sdd, usb stick, flash card (sd,cf). In general there is only a basic check by the operating system. This check is insufficient to guarantee no data loss. When using Linux there are some small tools that provide an enhanced check for data consistency. This is the first part that describes the usage of badblocks. Continue reading

Mocking Resources using JUnit @Rule

When writing unit tests in Java there might be the need to access a resource in the class that should be tested. A common way is to mock the resource. But mocking a simple resource is quite easy. This is supported by mocking frameworks like Mockito, EasyMock or PowerMock. It is a good idea in case you want to test a single action on the mocked resource – e.g. returning a value when accessing a map that contains master data. The following exmaple describes mocking a resource using Mockito. But in case there are complex operations on this resource mocking it is going to be really nasty.
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