J2SE SDK/JRE Version String Naming Convention

Developers may need to know a product's version string for various purposes, depending on whether they are developing and deploying a product or downloading and integrating a product.

The following table explains how to interpret SDK/JRE release version string information.

Note that this convention was not in effect prior to the 1.3.0 feature release. The output of java -version has had the same format since 1.3.1.

System Properties and the java -version Command

The output of the java -version command includes a product version identifier and a build identifier. This output is determined by the values of several system properties, and those system properties can themselves be examined programmatically at runtime.

System Property Name System Property Content Where Displayed in java -version Output
java.version
  • product version
  • Line one displays the product version.
java.runtime.version
  • product version
  • product build identifier
  • Line one displays the product version.
  • Line two displays the build identifier.

Numbering Format Specifications

Every SDK/JRE release that is shipped has a product version string and a build identifier associated with it. The general rules for setting either a version string or a build number string are as follows. For more specific rules and examples, see the following table:

  • The content of the java.version system property must always be unique for each external binary.
  • A separator is always used between different parts of the string so that ordering can be determined programmically. (For example, a version string of "1.3.1beta" is not acceptable. A version string of "1.3.1-beta" is acceptable.)
  • The format should be numeric and in lower case where applicable with a period "." within the field itself and a dash "-" between fields.
  • A period "." separator indicates a major version.
  • An underbar "_" separator is used to indicate an update release.
  • A dash "-" separator is used to indicate a non-GA (non-FCS) release.
  • A GA (FCS) product version or build identifier must not contain a dash (-).
  • No asterik "*" or plus sign "+" is allowed, since these are used as wildcards for the matching logic.
  • The content of the java.runtime.version system property can be expanded (beyond that of the java.version system property) to include the build id.
  • All GA (FCS) versions are ordered based on the standard dot-notation. For example: 1.3.0 < 1.3.0_01 < 1.3.1 < 1.3.1_01.

Syntax Notation

Syntax notation used in the following table is:
  • Italics indicate syntax that varies.
  • <- identifier> indicates syntax that is present only for any non-GA (non-FCS) release.

    The identifier is often used to represent a particular milestone, for example:

    • early access
    • beta
    • rc1

J2SE Release and Version String Information

Release Type Description Version Numbering Format Example java -version Output Strings
Feature Contains new functionality. n.n.0<- identifier>
  • The final digit is always a 0.
  • The - identifier is required for any non-GA (non-FCS) release.
  • A GA (FCS) release never has a - identifier.
The following output indicates a GA (FCS) release having a build identifier of b24. 

java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-b24)
Java HotSpot(TM) Client VM (build 1.3.0-b24, mixed mode)
Maintenance Contains engineering focused bug fixes. n.n.n<- identifier>
  • The final digit is never a 0.
  • The - identifier is required for any non-GA (non-FCS) release.
  • A GA (FCS) release never has a - identifier.
The following output indicates a beta, maintenance release having a build identifier of 09. 

java version "1.3.1-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1-beta-b09)
Java HotSpot(TM) Client VM (build 1.3.1_05-ea-b01, mixed mode)
Update Contains customer focused bug fixes. n.n.n_nn<- identifier>
  • The first three digits are identical to those of the feature or maintenance release that is being updated.
  • The two digits following the underbar indicate the update number. The higher the number, the more recent the update.
  • The - identifier is required for any non-GA (non-FCS) release.
  • A GA (FCS) release never has a - identifier.
The output indicates an early access, update release having a build identifier of b01. 

java version "1.3.1_05-ea"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1_05-ea-b01)
Java HotSpot(TM) Client VM (build 1.3.1_05-ea-b01, mixed mode)

The output indicates a GA (FCS) update release having a build identifier of b02.


java version "1.3.1_05"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.1_05-b02)
Java HotSpot(TM) Client VM (build 1.3.1_05-b02, mixed mode)

The output indicates an early access, update release having a build identifier of b01.


java version "1.4.0_03-ea"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0_03-ea-b01)
Java HotSpot(TM) Client VM (build 1.4.0_03-ea-b01, mixed mode)

The output indicates a GA (FCS) update release having a build identifier of b04.


java version "1.4.0_03"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0_03-b04)
Java HotSpot(TM) Client VM (build 1.4.0_03-b04, mixed mode)

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