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Comparing Java to .Net and C-sharp

Revision as of 20:48, 21 August 2010 by Ciaran (talk | contribs) (Related pages on {{SITENAME}}: ==References== {{reflist}})

With Oracle's patent attack on Google's Java-like Dalvik, many people asked if Java's patent risk is similar or higher than that of Microsoft's C# / Mono.

Who owns related patents?

For both languages, there is only one patent holder which asserts that it has patents on the language and is willing to take developers to court. For C#, that's Microsoft, and for Java, that's Oracle.

For Java there is also a patent which was owned by SCO until recently.[1][2] The current owner isn't known, but this patent has never been mentioned in relation to enforcement.

What forms of aggression have the patent holders shown?

Oracle sued Google in 2010.

Microsoft has long history of using their patents against software projects and companies, including free software projects.

What reassurances have the patent holders offered?

Java

  • Oracle (holder of all the worrying patents) has distributed a version of Java, called OpenJDK, under the terms of the GPLv2. In doing so, it has given an implicit grant to everyone that distributes and develops software based on that code, including modified versions, subsets, and supersets.
  • Oracle is a licensee of Open Invention Network, which means it has promised not to enforce its patents against the list of free software packages.
  • Oracle made a patent grant, in the Java Language Specification, that clean room implementations that are 100% compliant, are licensed to use Oracle's patents. However, this is possibly the least important patent grant since it doesn't apply to supersets, subsets, or any implementation that doesn't exactly comply with the Java Language Specification. This grant doesn't apply to OpenJDK and derivatives since grant itself says: "[...]license allows and is limited to the creation and distribution of clean room implementations[...]". It only apply for clean room implementations like Dalvik. Oracle-distributed OpenJDK is covered by GPL and allows supersetting and partial implementations as long is GPL obeyed.

C#

Microsoft gives the Microsoft Community Promise, which says:
Microsoft irrevocably promises not to assert any Microsoft Necessary Claims against you for making, using, selling, offering for sale, importing or distributing any implementation, to the extent it conforms to one of the Covered Specifications, and is compliant with all of the required parts of the mandatory provisions of that specification ("Covered Implementation"), subject to the following: [...]

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