# Class Runtime.Version

java.lang.Object
java.lang.Runtime.Version

All Implemented Interfaces:
  `Comparable<Runtime.Version>`

Enclosing class:
  `Runtime`

public static final class Runtime.Version extends Object implements Comparable<Runtime.Version>
A representation of a version string for an implementation of the Java SE Platform. A version string consists of a version number optionally followed by pre-release and build information.

## Version numbers

A version number, `$VNUM`, is a non-empty sequence of elements separated by period characters (U+002E). An element is either zero, or an unsigned integer numeral without leading zeros. The final element in a version number must not be zero. When an element is incremented, all subsequent elements are removed. The format is:

>     [1-9][0-9]*((\.0)*\.[1-9][0-9]*)*

The sequence may be of arbitrary length but the first four elements are assigned specific meanings, as follows:

>     $FEATURE.$INTERIM.$UPDATE.$PATCH

- `$FEATURE` — The feature-release counter, incremented for every feature release regardless of release content. Features may be added in a feature release; they may also be removed, if advance notice was given at least one feature release ahead of time. Incompatible changes may be made when justified.

- `$INTERIM` — The interim-release counter, incremented for non-feature releases that contain compatible bug fixes and enhancements but no incompatible changes, no feature removals, and no changes to standard APIs.

- `$UPDATE` — The update-release counter, incremented for compatible update releases that fix security issues, regressions, and bugs in newer features.

- `$PATCH` — The emergency patch-release counter, incremented only when it's necessary to produce an emergency release to fix a critical issue.

The fifth and later elements of a version number are free for use by platform implementors, to identify implementor-specific patch releases.

A version number never has trailing zero elements. If an element and all those that follow it logically have the value zero then all of them are omitted.

The sequence of numerals in a version number is compared to another such sequence in numerical, pointwise fashion; e.g., `10.0.4` is less than `10.1.2`. If one sequence is shorter than another then the missing elements of the shorter sequence are considered to be less than the corresponding elements of the longer sequence; e.g., `10.0.2` is less than `10.0.2.1`.

## Version strings

A version string, `$VSTR`, is a version number `$VNUM`, as described above, optionally followed by pre-release and build information, in one of the following formats:

>         $VNUM(-$PRE)?\+$BUILD(-$OPT)?
>         $VNUM-$PRE(-$OPT)?
>         $VNUM(\+-$OPT)?

where:

- `$PRE`, matching `([a-zA-Z0-9]+)` — A pre-release identifier. Typically `ea`, for a potentially unstable early-access release under active development, or `internal`, for an internal developer build.

- `$BUILD`, matching `(0|[1-9][0-9]*)` — The build number, incremented for each promoted build. `$BUILD` is reset to `1` when any portion of `$VNUM` is incremented.

- `$OPT`, matching `([-a-zA-Z0-9.]+)` — Additional build information, if desired. In the case of an `internal` build this will often contain the date and time of the build.

A version string `10-ea` matches `$VNUM = "10"` and `$PRE = "ea"`. The version string `10+-ea` matches `$VNUM = "10"` and `$OPT = "ea"`.

When comparing two version strings, the value of `$OPT`, if present, may or may not be significant depending on the chosen comparison method. The comparison methods `compareTo()` and `compareToIgnoreOptional()` should be used consistently with the corresponding methods `equals()` and `equalsIgnoreOptional()`.

A short version string, `$SVSTR`, often useful in less formal contexts, is a version number optionally followed by a pre-release identifier:

>         $VNUM(-$PRE)?

This is a value-based class; programmers should treat instances that are equal as interchangeable and should not use instances for synchronization, or unpredictable behavior may occur. For example, in a future release, synchronization may fail.

Since:
  9

- ## Method Summary

  Modifier and Type
  Method
  Description
  `Optional<Integer>`
  `build()`
  Returns the build number.
  `int`
  `compareTo(Runtime.Version obj)`
  Compares this version to another.
  `int`
  `compareToIgnoreOptional(Runtime.Version obj)`
  Compares this version to another disregarding optional build information.
  `boolean`
  `equals(Object obj)`
  Determines whether this `Version` is equal to another object.
  `boolean`
  `equalsIgnoreOptional(Object obj)`
  Determines whether this `Version` is equal to another disregarding optional build information.
  `int`
  `feature()`
  Returns the value of the feature element of the version number.
  `int`
  `hashCode()`
  Returns the hash code of this version.
  `int`
  `interim()`
  Returns the value of the interim element of the version number, or zero if it is absent.
  `int`
  `major()`
  Deprecated.
  As of Java SE 10, the first element of a version number is not the major-release number but the feature-release counter, incremented for every time-based release.
  `int`
  `minor()`
  Deprecated.
  As of Java SE 10, the second element of a version number is not the minor-release number but the interim-release counter, incremented for every interim release.
  `Optional<String>`
  `optional()`
  Returns optional additional identifying build information.
  `static Runtime.Version`
  `parse(String s)`
  Parses the given string as a valid version string containing a version number followed by pre-release and build information.
  `int`
  `patch()`
  Returns the value of the patch element of the version number, or zero if it is absent.
  `Optional<String>`
  `pre()`
  Returns the optional pre-release information.
  `int`
  `security()`
  Deprecated.
  As of Java SE 10, the third element of a version number is not the security level but the update-release counter, incremented for every update release.
  `String`
  `toString()`
  Returns a string representation of this version.
  `int`
  `update()`
  Returns the value of the update element of the version number, or zero if it is absent.
  `List<Integer>`
  `version()`
  Returns an unmodifiable `List` of the integers represented in the version number.

  ### Methods declared in class Object

  `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- ## Method Details

  - ### parse

    public static Runtime.Version parse(String s)
    Parses the given string as a valid version string containing a version number followed by pre-release and build information.
    Parameters:
      `s` - A string to interpret as a version
    Returns:
      The Version of the given string
    Throws:
      `IllegalArgumentException` - If the given string cannot be interpreted as a valid version
      `NullPointerException` - If the given string is `null`
      `NumberFormatException` - If an element of the version number or the build number cannot be represented as an `Integer`

  - ### feature

    public int feature()
    Returns the value of the feature element of the version number.
    Returns:
      The value of the feature element
    Since:
      10

  - ### interim

    public int interim()
    Returns the value of the interim element of the version number, or zero if it is absent.
    Returns:
      The value of the interim element, or zero
    Since:
      10

  - ### update

    public int update()
    Returns the value of the update element of the version number, or zero if it is absent.
    Returns:
      The value of the update element, or zero
    Since:
      10

  - ### patch

    public int patch()
    Returns the value of the patch element of the version number, or zero if it is absent.
    Returns:
      The value of the patch element, or zero
    Since:
      10

  - ### major

    @Deprecated(since="10") public int major()
    Deprecated.
    As of Java SE 10, the first element of a version number is not the major-release number but the feature-release counter, incremented for every time-based release. Use the `feature()` method in preference to this method. For compatibility, this method returns the value of the feature element.
    Returns the value of the major element of the version number.
    Returns:
      The value of the feature element

  - ### minor

    @Deprecated(since="10") public int minor()
    Deprecated.
    As of Java SE 10, the second element of a version number is not the minor-release number but the interim-release counter, incremented for every interim release. Use the `interim()` method in preference to this method. For compatibility, this method returns the value of the interim element, or zero if it is absent.
    Returns the value of the minor element of the version number, or zero if it is absent.
    Returns:
      The value of the interim element, or zero

  - ### security

    @Deprecated(since="10") public int security()
    Deprecated.
    As of Java SE 10, the third element of a version number is not the security level but the update-release counter, incremented for every update release. Use the `update()` method in preference to this method. For compatibility, this method returns the value of the update element, or zero if it is absent.
    Returns the value of the security element of the version number, or zero if it is absent.
    Returns:
      The value of the update element, or zero

  - ### version

    public List<Integer> version()
    Returns an unmodifiable `List` of the integers represented in the version number. The `List` always contains at least one element corresponding to the feature version number.
    Returns:
      An unmodifiable list of the integers represented in the version number

  - ### pre

    public Optional<String> pre()
    Returns the optional pre-release information.
    Returns:
      The optional pre-release information as a String

  - ### build

    public Optional<Integer> build()
    Returns the build number.
    Returns:
      The optional build number.

  - ### optional

    public Optional<String> optional()
    Returns optional additional identifying build information.
    Returns:
      Additional build information as a String

  - ### compareTo

    public int compareTo(Runtime.Version obj)
    Compares this version to another.

    Each of the components in the version is compared in the following order of precedence: version numbers, pre-release identifiers, build numbers, optional build information.

    Comparison begins by examining the sequence of version numbers. If one sequence is shorter than another, then the missing elements of the shorter sequence are considered to be less than the corresponding elements of the longer sequence.

    A version with a pre-release identifier is always considered to be less than a version without one. Pre-release identifiers are compared numerically when they consist only of digits, and lexicographically otherwise. Numeric identifiers are considered to be less than non-numeric identifiers.

    A version without a build number is always less than one with a build number; otherwise build numbers are compared numerically.

    The optional build information is compared lexicographically. During this comparison, a version with optional build information is considered to be greater than a version without one.

    Specified by:
      `compareTo` in interface `Comparable<Runtime.Version>`
    Parameters:
      `obj` - The object to be compared
    Returns:
      A negative integer, zero, or a positive integer if this `Version` is less than, equal to, or greater than the given `Version`
    Throws:
      `NullPointerException` - If the given object is `null`

  - ### compareToIgnoreOptional

    public int compareToIgnoreOptional(Runtime.Version obj)
    Compares this version to another disregarding optional build information.

    Two versions are compared by examining the version string as described in `compareTo(Version)` with the exception that the optional build information is always ignored.

    This method provides ordering which is consistent with `equalsIgnoreOptional()`.

    Parameters:
      `obj` - The object to be compared
    Returns:
      A negative integer, zero, or a positive integer if this `Version` is less than, equal to, or greater than the given `Version`
    Throws:
      `NullPointerException` - If the given object is `null`

  - ### toString

    public String toString()
    Returns a string representation of this version.
    Overrides:
      `toString` in class `Object`
    Returns:
      The version string

  - ### equals

    public boolean equals(Object obj)
    Determines whether this `Version` is equal to another object.

    Two `Version`s are equal if and only if they represent the same version string.

    Overrides:
      `equals` in class `Object`
    Parameters:
      `obj` - The object to which this `Version` is to be compared
    Returns:
      `true` if, and only if, the given object is a `Version` that is identical to this `Version`
    See Also:
      - `Object.hashCode()`
      - `HashMap`

  - ### equalsIgnoreOptional

    public boolean equalsIgnoreOptional(Object obj)
    Determines whether this `Version` is equal to another disregarding optional build information.

    Two `Version`s are equal if and only if they represent the same version string disregarding the optional build information.

    Parameters:
      `obj` - The object to which this `Version` is to be compared
    Returns:
      `true` if, and only if, the given object is a `Version` that is identical to this `Version` ignoring the optional build information

  - ### hashCode

    public int hashCode()
    Returns the hash code of this version.
    Overrides:
      `hashCode` in class `Object`
    Returns:
      The hashcode of this version
    See Also:
      - `Object.equals(java.lang.Object)`
      - `System.identityHashCode(Object)`