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Up until around January 2013, the minor updates of major Java versions were always consecutive: 6u30, 6u31, 6u32, 6u33 and so on. The same is true for Java 7 updates.

But, starting around January or February 2013, some minor version numberings were skipped. Take a look here: As you can see, the minor updates are 7u10, 7u11, 7u13, 7u15, 7u17, 7u21, 7u25. Where did 7u12, 7u14, 7u16 etc. dissapear ? Was there a specific reason why they were skipped ?

If they were actually faulty and couldn't be released, then:

  • how come there is no significant uptake in the time-gap between them ?
  • how come up until January/February this year this never happened, but is constantly happening ever since ?

I tried searching for an answer to this, but couldn't find anything. So I thought someone here might have a clue about this.

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up vote 7 down vote accepted

Orace has adopted a pretty weird numbering scheme:

Since the initial release of JDK 5.0, Java update releases have either been Limited Update releases that include new functionality and non-security fixes or Critical Patch Updates (CPUs) that only include fixes for security vulnerabilities. We will continue releasing Limited Update and CPU Java releases, however we are changing the frequency and way in which these releases are numbered:

  • Limited Update releases will be numbered in multiples of 20.
  • We intend for Critical Patch Updates to continue to use odd numbers. The numbers will be calculated by adding multiples of five to the prior Limited Update and when needed adding one to keep the resulting number odd.


This numbering scheme will leave several numbers between releases which will allow us to insert releases – for example security alerts or support releases, should that become necessary - without having to renumber later releases.

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