How do you compare two version Strings in Java?

Question

Is there a standard idiom for comparing version numbers? I can't just use a straight String compareTo because I don't know yet what the maximum number of point releases there will be. I need to compare the versions and have the following hold true:

1.0 < 1.1
1.0.1 < 1.1
1.9 < 1.10

Servia

Have you tried to just remove the dots and parse the resulting string as an integer? I'm currently using something similar to the following: String version = "1.1.2".replace(".", ""); int number = Integer.parseInt(version); // = 112. You could compare the number to another one and thus find the version that's more recent. Additionally you may check if the version string matches some certain pattern like \\d+\\.\\d+\\.\\d to make the result has at least 3 digits. – Sphalerite

@RegisteredUser How would this work with something like this: 1.12.1 and 1.1.34 ? – Ozellaozen

You would have to make sure each part has the same size in length. So to compare the two versions of your example they must be something like this: 1.12.01 and 1.01.34. In java you could achieve this by first splitting at the . character and the compare each elements length. Afterwards just put all elements into one string, then parse it as int and then compare it to the other version that has been converted the same way – Sphalerite

Just wanted to share that this could be surprisingly short implemented in groovy https://mcmap.net/q/41964/-compare-version-strings-in-groovy – Craftsman

Answer 1

Tokenize the strings with the dot as delimiter and then compare the integer translation side by side, beginning from the left.

Chemo

and don't forget you might not always have only numbers. some apps will include build numbers, and might include things like 1.0.1b for beta/etc. – Photochronograph

How do you do this? – Karr

You write a regex that splits the string into digit and non-digit sections. Compare the digits sections numerically and the non-digit sections lexicographically. (maybe also split at dots.) – Giroux

it will not work in case ".1" and "1". Similarly, there might be other use-cases – Systematics

It is 2020, and I'd say use semver. See baeldung.com/java-comparing-versions – Matazzoni

I thought to say semver, too. But I came back as semver requires at least three components and this question is more open. – Croup

Answer 2

Another solution for this old post (for those that it might help) :

public class Version implements Comparable<Version> {

    private String version;

    public final String get() {
        return this.version;
    }

    public Version(String version) {
        if(version == null)
            throw new IllegalArgumentException("Version can not be null");
        if(!version.matches("[0-9]+(\\.[0-9]+)*"))
            throw new IllegalArgumentException("Invalid version format");
        this.version = version;
    }

    @Override public int compareTo(Version that) {
        if(that == null)
            return 1;
        String[] thisParts = this.get().split("\\.");
        String[] thatParts = that.get().split("\\.");
        int length = Math.max(thisParts.length, thatParts.length);
        for(int i = 0; i < length; i++) {
            int thisPart = i < thisParts.length ?
                Integer.parseInt(thisParts[i]) : 0;
            int thatPart = i < thatParts.length ?
                Integer.parseInt(thatParts[i]) : 0;
            if(thisPart < thatPart)
                return -1;
            if(thisPart > thatPart)
                return 1;
        }
        return 0;
    }

    @Override public boolean equals(Object that) {
        if(this == that)
            return true;
        if(that == null)
            return false;
        if(this.getClass() != that.getClass())
            return false;
        return this.compareTo((Version) that) == 0;
    }

}

---

Version a = new Version("1.1");
Version b = new Version("1.1.1");
a.compareTo(b) // return -1 (a<b)
a.equals(b)    // return false

Version a = new Version("2.0");
Version b = new Version("1.9.9");
a.compareTo(b) // return 1 (a>b)
a.equals(b)    // return false

Version a = new Version("1.0");
Version b = new Version("1");
a.compareTo(b) // return 0 (a=b)
a.equals(b)    // return true

Version a = new Version("1");
Version b = null;
a.compareTo(b) // return 1 (a>b)
a.equals(b)    // return false

List<Version> versions = new ArrayList<Version>();
versions.add(new Version("2"));
versions.add(new Version("1.0.5"));
versions.add(new Version("1.01.0"));
versions.add(new Version("1.00.1"));
Collections.min(versions).get() // return min version
Collections.max(versions).get() // return max version

// WARNING
Version a = new Version("2.06");
Version b = new Version("2.060");
a.equals(b)    // return false

---

Edit:

@daiscog: Thank you for your remark, this piece of code has been developed for the Android platform and as recommended by Google, the method "matches" check the entire string unlike Java that uses a regulatory pattern. (Android documentation - JAVA documentation)

Lamothe

This is the best solution IMHO. I restricted it to 3 element version codes by changing it to if (!version.matches("[0-9]+(\\.[0-9]+){0,2}") and by adding a variable: private static final int[] PRIME = { 2, 3, 5 }; I was able to create the missing hashCode for the above: @Override public final int hashCode() { final String[] parts = this.get().split("\\."); int hashCode = 0; for (int i = 0; i < parts.length; i++) { final int part = Integer.parseInt(parts[i]); if (part > 0) { hashCode += PRIME[i] ^ part; } } return hashCode; } – Roan

You should at least cache the implicit calls to Pattern.compile(), given that your logic is called with O(N log N) complexity. – Priestcraft

this implementation overrides equals(Object that) and should therefore override hashCode(). Two objects that are equal must return the same hashCode otherwise you can get in trouble if you use these objects with hashed collections. – Oleander

You can't hash on the version string since 'new Version("1.0").equals(new Version("1")' will return true. This will work, but is inefficient ... // contract: any two Versions that are equal must return the same hashCode. // since "1.0" equals "1", we can't return the hashCode of the version string. @Override public int hashCode() { return 1; } – Oleander

converted on Kotlin https://mcmap.net/q/41886/-how-do-you-compare-two-version-strings-in-java – Dodecasyllable

You should parse the String and store the integers in the constructor instead of parsing the string in each compareTo(Version) call because parsing at each call is very, very expensive. Keep the string as well for the get(), though. – Langley

Answer 3

It's really easy using Maven:

import org.apache.maven.artifact.versioning.DefaultArtifactVersion;

DefaultArtifactVersion minVersion = new DefaultArtifactVersion("1.0.1");
DefaultArtifactVersion maxVersion = new DefaultArtifactVersion("1.10");

DefaultArtifactVersion version = new DefaultArtifactVersion("1.11");

if (version.compareTo(minVersion) < 0 || version.compareTo(maxVersion) > 0) {
    System.out.println("Sorry, your version is unsupported");
}

You can get the right dependency string for Maven Artifact from this page:

<dependency>
<groupId>org.apache.maven</groupId>
<artifactId>maven-artifact</artifactId>
<version>3.0.3</version>
</dependency>

Cayes

I have created a gist with tests on how this can be done: gist.github.com/2627608 – Wellfounded

only one worry is: to use this dependency with lots of files in it just to one reason - to have one class - DefaultArtifactVersion – Toxoplasmosis

@Toxoplasmosis storage is cheap - certainly cheaper than writing, testing and maintaining original code – Cayes

Note that Comparable.compareTo is documented as returning "a negative integer, zero, or a positive integer", so it's a good habit to avoid checking for -1 and +1. – Precontract

@AlexDean made minor edit to utilize > and < to compare as stated by documentation (as pointed out by @seanf). Also, why did you use DefaultArtifactVersion instead of ComparableVersion. – Marcomarconi

Apparently my edit did not go through (trying again). As @DavidWallace and seanf point out, the above code is incorrect. Alex, if you catch this, could you make the edit. – Marcomarconi

That does not seem to work with version Strings of different length: new DefaultArtifactVersion("1.2.1.1").compareTo(new DefaultArtifactVersion("1.1")) results in -1. – Mclendon

DefaultArtifactVersion: github.com/apache/maven/blob/master/maven-artifact/src/main/… – Achelous

Manuel M - I just ran this test and it succeeds: int res = new DefaultArtifactVersion("1.2.1.1").compareTo(new DefaultArtifactVersion("1.1.8.7.6.7.8.9")); Assert.assertTrue(res > 0); – Fornof

Answer 4

Use Java 9's own builtin Version class

import java.util.*;
import java.lang.module.ModuleDescriptor.Version;
class Main {
  public static void main(String[] args) {
    var versions = Arrays.asList(
      "1.0.2",
      "1.0.0-beta.2",
      "1.0.0",
      "1.0.0-beta",
      "1.0.0-alpha.12",
      "1.0.0-beta.11",
      "1.0.1",
      "1.0.11",
      "1.0.0-rc.1",
      "1.0.0-alpha.1",
      "1.1.0",
      "1.0.0-alpha.beta",
      "1.11.0",
      "1.0.0-alpha.12.ab-c",
      "0.0.1",
      "1.2.1",
      "1.0.0-alpha",
      "1.0.0.1",  // Also works with a number of sections different than 3
      "1.0.0.2",
      "2",
      "10",
      "1.0.0.10"
    );
    versions.stream()
      .map(Version::parse)
      .sorted()
      .forEach(System.out::println);
  }
}

Try it online!

Output:

0.0.1
1.0.0-alpha
1.0.0-alpha.1
1.0.0-alpha.12
1.0.0-alpha.12.ab-c
1.0.0-alpha.beta
1.0.0-beta
1.0.0-beta.2
1.0.0-beta.11
1.0.0-rc.1
1.0.0
1.0.0.1
1.0.0.2
1.0.0.10
1.0.1
1.0.2
1.0.11
1.1.0
1.2.1
1.11.0
2
10

Darvon

Sorry, I'm not sure an app or lib should have to import java.lang.module.ModuleDescriptor.Version to do a version compare. This is created to compare modules. – Carmeliacarmelina

Answer 5

You need to normalise the version strings so they can be compared. Something like

import java.util.regex.Pattern;

public class Main {
    public static void main(String... args) {
        compare("1.0", "1.1");
        compare("1.0.1", "1.1");
        compare("1.9", "1.10");
        compare("1.a", "1.9");
    }

    private static void compare(String v1, String v2) {
        String s1 = normalisedVersion(v1);
        String s2 = normalisedVersion(v2);
        int cmp = s1.compareTo(s2);
        String cmpStr = cmp < 0 ? "<" : cmp > 0 ? ">" : "==";
        System.out.printf("'%s' %s '%s'%n", v1, cmpStr, v2);
    }

    public static String normalisedVersion(String version) {
        return normalisedVersion(version, ".", 4);
    }

    public static String normalisedVersion(String version, String sep, int maxWidth) {
        String[] split = Pattern.compile(sep, Pattern.LITERAL).split(version);
        StringBuilder sb = new StringBuilder();
        for (String s : split) {
            sb.append(String.format("%" + maxWidth + 's', s));
        }
        return sb.toString();
    }
}

Prints

'1.0' < '1.1'
'1.0.1' < '1.1'
'1.9' < '1.10'
'1.a' > '1.9'

Nucleoprotein

Caveat to normalization is the implied max width you have in there. – Doak

@IHeartAndroid Good point, Unless you expect '4.1' == '4.1.0' I think this is a sense ordering. – Nucleoprotein

Answer 6

The best to reuse existing code, take Maven's ComparableVersion class

advantages:

• Apache License, Version 2.0,
• tested,
• used (copied) in multiple projects like spring-security-core, jboss etc
• multiple features
• it's already a java.lang.Comparable
• just copy-paste that one class, no third-party dependencies

Don't include dependency to maven-artifact as that will pull various transitive dependencies

Studious

This reads like an advertisement and doesn't add anything to the other answers. – Dunson

This relevant to the question as it was about standard method to compare versions and maven version comparison is pretty much standard. – Marla

Disadvantage: Pulls in a host of dependencies, which means a host of attack surface and potential for version conflicts. – Giroux

@toolforger, the last line of the answer advises to not use the artifact as a dependency. Instead, you can just copy the file. Like said (twice) inside the advantages list. – Bourque

@ДмитрийКулешов Ah right I overlooked that. Though copying a class means you lose the updating from the upstream project and take responsibility for keeping all the other properties intact; that trade-off should have been mentioned. – Giroux

That link does not work for me... try this one: github.com/apache/maven/blob/master/maven-artifact/src/main/… – Shogunate

Answer 7

// VersionComparator.java
import java.util.Comparator;

public class VersionComparator implements Comparator {

    public boolean equals(Object o1, Object o2) {
        return compare(o1, o2) == 0;
    }

    public int compare(Object o1, Object o2) {
        String version1 = (String) o1;
        String version2 = (String) o2;

        VersionTokenizer tokenizer1 = new VersionTokenizer(version1);
        VersionTokenizer tokenizer2 = new VersionTokenizer(version2);

        int number1 = 0, number2 = 0;
        String suffix1 = "", suffix2 = "";

        while (tokenizer1.MoveNext()) {
            if (!tokenizer2.MoveNext()) {
                do {
                    number1 = tokenizer1.getNumber();
                    suffix1 = tokenizer1.getSuffix();
                    if (number1 != 0 || suffix1.length() != 0) {
                        // Version one is longer than number two, and non-zero
                        return 1;
                    }
                }
                while (tokenizer1.MoveNext());

                // Version one is longer than version two, but zero
                return 0;
            }

            number1 = tokenizer1.getNumber();
            suffix1 = tokenizer1.getSuffix();
            number2 = tokenizer2.getNumber();
            suffix2 = tokenizer2.getSuffix();

            if (number1 < number2) {
                // Number one is less than number two
                return -1;
            }
            if (number1 > number2) {
                // Number one is greater than number two
                return 1;
            }

            boolean empty1 = suffix1.length() == 0;
            boolean empty2 = suffix2.length() == 0;

            if (empty1 && empty2) continue; // No suffixes
            if (empty1) return 1; // First suffix is empty (1.2 > 1.2b)
            if (empty2) return -1; // Second suffix is empty (1.2a < 1.2)

            // Lexical comparison of suffixes
            int result = suffix1.compareTo(suffix2);
            if (result != 0) return result;

        }
        if (tokenizer2.MoveNext()) {
            do {
                number2 = tokenizer2.getNumber();
                suffix2 = tokenizer2.getSuffix();
                if (number2 != 0 || suffix2.length() != 0) {
                    // Version one is longer than version two, and non-zero
                    return -1;
                }
            }
            while (tokenizer2.MoveNext());

            // Version two is longer than version one, but zero
            return 0;
        }
        return 0;
    }
}

// VersionTokenizer.java
public class VersionTokenizer {
    private final String _versionString;
    private final int _length;

    private int _position;
    private int _number;
    private String _suffix;
    private boolean _hasValue;

    public int getNumber() {
        return _number;
    }

    public String getSuffix() {
        return _suffix;
    }

    public boolean hasValue() {
        return _hasValue;
    }

    public VersionTokenizer(String versionString) {
        if (versionString == null)
            throw new IllegalArgumentException("versionString is null");

        _versionString = versionString;
        _length = versionString.length();
    }

    public boolean MoveNext() {
        _number = 0;
        _suffix = "";
        _hasValue = false;

        // No more characters
        if (_position >= _length)
            return false;

        _hasValue = true;

        while (_position < _length) {
            char c = _versionString.charAt(_position);
            if (c < '0' || c > '9') break;
            _number = _number * 10 + (c - '0');
            _position++;
        }

        int suffixStart = _position;

        while (_position < _length) {
            char c = _versionString.charAt(_position);
            if (c == '.') break;
            _position++;
        }

        _suffix = _versionString.substring(suffixStart, _position);

        if (_position < _length) _position++;

        return true;
    }
}

Example:

public class Main
{
    private static VersionComparator cmp;

    public static void main (String[] args)
    {
        cmp = new VersionComparator();
        Test(new String[]{"1.1.2", "1.2", "1.2.0", "1.2.1", "1.12"});
        Test(new String[]{"1.3", "1.3a", "1.3b", "1.3-SNAPSHOT"});
    }

    private static void Test(String[] versions) {
        for (int i = 0; i < versions.length; i++) {
            for (int j = i; j < versions.length; j++) {
                Test(versions[i], versions[j]);
            }
        }
    }

    private static void Test(String v1, String v2) {
        int result = cmp.compare(v1, v2);
        String op = "==";
        if (result < 0) op = "<";
        if (result > 0) op = ">";
        System.out.printf("%s %s %s\n", v1, op, v2);
    }
}

Output:

1.1.2 == 1.1.2                --->  same length and value
1.1.2 < 1.2                   --->  first number (1) less than second number (2) => -1
1.1.2 < 1.2.0                 --->  first number (1) less than second number (2) => -1
1.1.2 < 1.2.1                 --->  first number (1) less than second number (2) => -1
1.1.2 < 1.12                  --->  first number (1) less than second number (12) => -1
1.2 == 1.2                    --->  same length and value
1.2 == 1.2.0                  --->  first shorter than second, but zero
1.2 < 1.2.1                   --->  first shorter than second, and non-zero
1.2 < 1.12                    --->  first number (2) less than second number (12) => -1
1.2.0 == 1.2.0                --->  same length and value
1.2.0 < 1.2.1                 --->  first number (0) less than second number (1) => -1
1.2.0 < 1.12                  --->  first number (2) less than second number (12) => -1
1.2.1 == 1.2.1                --->  same length and value
1.2.1 < 1.12                  --->  first number (2) less than second number (12) => -1
1.12 == 1.12                  --->  same length and value

1.3 == 1.3                    --->  same length and value
1.3 > 1.3a                    --->  first suffix ('') is empty, but not second ('a') => 1
1.3 > 1.3b                    --->  first suffix ('') is empty, but not second ('b') => 1
1.3 > 1.3-SNAPSHOT            --->  first suffix ('') is empty, but not second ('-SNAPSHOT') => 1
1.3a == 1.3a                  --->  same length and value
1.3a < 1.3b                   --->  first suffix ('a') compared to second suffix ('b') => -1
1.3a < 1.3-SNAPSHOT           --->  first suffix ('a') compared to second suffix ('-SNAPSHOT') => -1
1.3b == 1.3b                  --->  same length and value
1.3b < 1.3-SNAPSHOT           --->  first suffix ('b') compared to second suffix ('-SNAPSHOT') => -1
1.3-SNAPSHOT == 1.3-SNAPSHOT  --->  same length and value

Nonstop

Thanks for this. I'm using perhaps a very old version of Java in my Eclipse (even if it's already 18.0.1.1 when I check it in powershell), so the trending answer here doesn't work for me. – Snoddy

Answer 8

Wondering why everybody assumes that the versions is only made up of integers - in my case it was not.

Why reinventing the wheel (assuming the version follows the Semver standard)

First install https://github.com/vdurmont/semver4j via Maven

Then use this library

Semver sem = new Semver("1.2.3");
sem.isGreaterThan("1.2.2"); // true

Thuggee

Answer 9

public static int compareVersions(String version1, String version2){

    String[] levels1 = version1.split("\\.");
    String[] levels2 = version2.split("\\.");

    int length = Math.max(levels1.length, levels2.length);
    for (int i = 0; i < length; i++){
        Integer v1 = i < levels1.length ? Integer.parseInt(levels1[i]) : 0;
        Integer v2 = i < levels2.length ? Integer.parseInt(levels2[i]) : 0;
        int compare = v1.compareTo(v2);
        if (compare != 0){
            return compare;
        }
    }

    return 0;
}

Pontiac

based on your idea https://mcmap.net/q/41886/-how-do-you-compare-two-version-strings-in-java – Heyday

Answer 10

If you already have Jackson in your project, you can use com.fasterxml.jackson.core.Version:

import com.fasterxml.jackson.core.Version;
import org.junit.Test;

import static org.junit.Assert.assertTrue;

public class VersionTest {

    @Test
    public void shouldCompareVersion() {
        Version version1 = new Version(1, 11, 1, null, null, null);
        Version version2 = new Version(1, 12, 1, null, null, null);
        assertTrue(version1.compareTo(version2) < 0);
    }
}

Distaste

Answer 11

I done it right now and asked myself, is it correct? Because I've never found a cleanest solution before than mine:

You just need to split the string versions ("1.0.0") like this example:

userVersion.split("\\.")

Then you will have: {"1", "0", "0"}

Now, using the method that I done:

isUpdateAvailable(userVersion.split("\\."), latestVersionSplit.split("\\."));

Method:

/**
 * Compare two versions
 *
 * @param userVersionSplit   - User string array with major, minor and patch version from user (exemple: {"5", "2", "70"})
 * @param latestVersionSplit - Latest string array with major, minor and patch version from api (example: {"5", "2", "71"})
 * @return true if user version is smaller than latest version
 */
public static boolean isUpdateAvailable(String[] userVersionSplit, String[] latestVersionSplit) {

    try {
        int majorUserVersion = Integer.parseInt(userVersionSplit[0]);
        int minorUserVersion = Integer.parseInt(userVersionSplit[1]);
        int patchUserVersion = Integer.parseInt(userVersionSplit[2]);

        int majorLatestVersion = Integer.parseInt(latestVersionSplit[0]);
        int minorLatestVersion = Integer.parseInt(latestVersionSplit[1]);
        int patchLatestVersion = Integer.parseInt(latestVersionSplit[2]);

        if (majorUserVersion <= majorLatestVersion) {
            if (majorUserVersion < majorLatestVersion) {
                return true;
            } else {
                if (minorUserVersion <= minorLatestVersion) {
                    if (minorUserVersion < minorLatestVersion) {
                        return true;
                    } else {
                        return patchUserVersion < patchLatestVersion;
                    }
                }
            }
        }
    } catch (Exception ignored) {
        // Will be throw only if the versions pattern is different from "x.x.x" format
        // Will return false at the end
    }

    return false;
}

Waiting for any feedback :)

Whistling

A warning to anyone who is wring kotlin but coming for this answer, don't use this. in parameter for Java String.split is regex, but kotlin in parameter is string. It means for kotlin string.split(".") is sufficient. – Glyptic

Answer 12

@alex's post on Kotlin

class Version(inputVersion: String) : Comparable<Version> {

        var version: String
            private set

        override fun compareTo(other: Version) =
            (split() to other.split()).let {(thisParts, thatParts)->
                val length = max(thisParts.size, thatParts.size)
                for (i in 0 until length) {
                    val thisPart = if (i < thisParts.size) thisParts[i].toInt() else 0
                    val thatPart = if (i < thatParts.size) thatParts[i].toInt() else 0
                    if (thisPart < thatPart) return -1
                    if (thisPart > thatPart) return 1
                }
                 0
            }

        init {
            require(inputVersion.matches("[0-9]+(\\.[0-9]+)*".toRegex())) { "Invalid version format" }
            version = inputVersion
        }
    }

    fun Version.split() = version.split(".").toTypedArray()

usage:

Version("1.2.4").compareTo(Version("0.0.5")) //return 1

Dodecasyllable

Instead of override fun compareTo(other: Version) you can use operator fun compareTo(version: Version): Int and avoid the java-esk : Comparable<Version> – Durstin

Answer 13

public int compare(String v1, String v2) {
        v1 = v1.replaceAll("\\s", "");
        v2 = v2.replaceAll("\\s", "");
        String[] a1 = v1.split("\\.");
        String[] a2 = v2.split("\\.");
        List<String> l1 = Arrays.asList(a1);
        List<String> l2 = Arrays.asList(a2);


        int i=0;
        while(true){
            Double d1 = null;
            Double d2 = null;

            try{
                d1 = Double.parseDouble(l1.get(i));
            }catch(IndexOutOfBoundsException e){
            }

            try{
                d2 = Double.parseDouble(l2.get(i));
            }catch(IndexOutOfBoundsException e){
            }

            if (d1 != null && d2 != null) {
                if (d1.doubleValue() > d2.doubleValue()) {
                    return 1;
                } else if (d1.doubleValue() < d2.doubleValue()) {
                    return -1;
                }
            } else if (d2 == null && d1 != null) {
                if (d1.doubleValue() > 0) {
                    return 1;
                }
            } else if (d1 == null && d2 != null) {
                if (d2.doubleValue() > 0) {
                    return -1;
                }
            } else {
                break;
            }
            i++;
        }
        return 0;
    }

Sowell

Answer 14

/**  
 *  written by: Stan Towianski - May 2018 
 * notes: I make assumption each of 3 version sections a.b.c is not longer then 4 digits: aaaa.bbbb.cccc-MODWORD1(-)modnum2
 * 5.10.13-release-1 becomes 0000500100013.501     6.0-snapshot becomes 0000600000000.100
 * MODWORD1 = -xyz/NotMatching, -SNAPSHOT, -ALPHA, -BETA, -RC, -RELEASE/nothing  return:  .0, .1, .2, .3, .4, .5
 * modnum2 = up to 2 digit/chars second version
 * */
public class VersionCk {

    private static boolean isVersionHigher( String baseVersion, String testVersion )
        {
        System.out.println( "versionToComparable( baseVersion ) =" + versionToComparable( baseVersion ) );
        System.out.println( "versionToComparable( testVersion ) =" + versionToComparable( testVersion ) + " is this higher ?" );
        return versionToComparable( testVersion ).compareTo( versionToComparable( baseVersion ) ) > 0;
        }

    //----  not worrying about += for something so small
    private static String versionToComparable( String version )
        {
//        System.out.println("version - " + version);
        String versionNum = version;
        int at = version.indexOf( '-' );
        if ( at >= 0 )
            versionNum = version.substring( 0, at );

        String[] numAr = versionNum.split( "\\." );
        String versionFormatted = "0";
        for ( String tmp : numAr )
            {
            versionFormatted += String.format( "%4s", tmp ).replace(' ', '0');
            }
        while ( versionFormatted.length() < 12 )  // pad out to aaaa.bbbb.cccc
            {
            versionFormatted += "0000";
            }
//        System.out.println( "converted min version =" + versionFormatted + "=   : " + versionNum );
        return versionFormatted + getVersionModifier( version, at );
        }

    //----  use order low to high: -xyz, -SNAPSHOT, -ALPHA, -BETA, -RC, -RELEASE/nothing  returns: 0, 1, 2, 3, 4, 5
    private static String getVersionModifier( String version, int at )
        {
//        System.out.println("version - " + version );
        String[] wordModsAr = { "-SNAPSHOT", "-ALPHA", "-BETA", "-RC", "-RELEASE" };        

        if ( at < 0 )
            return "." + wordModsAr.length + "00";   // make nothing = RELEASE level

        int i = 1;
        for ( String word : wordModsAr )
            {
            if ( ( at = version.toUpperCase().indexOf( word ) ) > 0 )
                return "." + i + getSecondVersionModifier( version.substring( at + word.length() ) );
            i++;
            }

        return ".000";
        }

    //----  add 2 chars for any number after first modifier.  -rc2 or -rc-2   returns 02
    private static String getSecondVersionModifier( String version )
        {
        System.out.println( "second modifier =" + version + "=" );
        Matcher m = Pattern.compile("(.*?)(\\d+).*").matcher( version );
//        if ( m.matches() )
//            System.out.println( "match ? =" + m.matches() + "=   m.group(1) =" + m.group(1) + "=   m.group(2) =" + m.group(2) + "=   m.group(3) =" + (m.groupCount() >= 3 ? m.group(3) : "x") );
//        else
//            System.out.println( "No match" );
        return m.matches() ? String.format( "%2s", m.group(2) ).replace(' ', '0') : "00";
        }

    public static void main(String[] args) 
        {
        checkVersion( "3.10.0", "3.4.0");
        checkVersion( "5.4.2", "5.4.1");
        checkVersion( "5.4.4", "5.4.5");
        checkVersion( "5.4.9", "5.4.12");
        checkVersion( "5.9.222", "5.10.12");
        checkVersion( "5.10.12", "5.10.12");
        checkVersion( "5.10.13", "5.10.14");
        checkVersion( "6.7.0", "6.8");
        checkVersion( "6.7", "2.7.0");
        checkVersion( "6", "6.3.1");
        checkVersion( "4", "4.0.0");
        checkVersion( "6.3.0", "6");
        checkVersion( "5.10.12-Alpha", "5.10.12-beTA");
        checkVersion( "5.10.13-release", "5.10.14-beta");
        checkVersion( "6.7.0", "6.8-snapshot");
        checkVersion( "6.7.1", "6.7.0-release");
        checkVersion( "6-snapshot", "6.0.0-beta");
        checkVersion( "6.0-snapshot", "6.0.0-whatthe");
        checkVersion( "5.10.12-Alpha-1", "5.10.12-alpha-2");
        checkVersion( "5.10.13-release-1", "5.10.13-release2");
        checkVersion( "10-rc42", "10.0.0-rc53");
        }

    private static void checkVersion(String baseVersion, String testVersion) 
        {
        System.out.println( "baseVersion - " + baseVersion );
        System.out.println( "testVersion - " + testVersion );
        System.out.println( "isVersionHigher = " + isVersionHigher( baseVersion, testVersion ) );
        System.out.println( "---------------");
        }

    }

some output:

---------------
baseVersion - 6.7
testVersion - 2.7.0
versionToComparable( baseVersion ) =0000600070000.500
versionToComparable( testVersion ) =0000200070000.500 is this higher ?
isVersionHigher = false
---------------
baseVersion - 6
testVersion - 6.3.1
versionToComparable( baseVersion ) =0000600000000.500
versionToComparable( testVersion ) =0000600030001.500 is this higher ?
isVersionHigher = true
---------------
baseVersion - 4
testVersion - 4.0.0
versionToComparable( baseVersion ) =0000400000000.500
versionToComparable( testVersion ) =0000400000000.500 is this higher ?
isVersionHigher = false
---------------
baseVersion - 6.3.0
testVersion - 6
versionToComparable( baseVersion ) =0000600030000.500
versionToComparable( testVersion ) =0000600000000.500 is this higher ?
isVersionHigher = false
---------------
baseVersion - 5.10.12-Alpha
testVersion - 5.10.12-beTA
second modifier ==
versionToComparable( baseVersion ) =0000500100012.200
second modifier ==
versionToComparable( testVersion ) =0000500100012.300 is this higher ?
second modifier ==
second modifier ==
isVersionHigher = true
---------------
baseVersion - 5.10.13-release
testVersion - 5.10.14-beta
second modifier ==
versionToComparable( baseVersion ) =0000500100013.500
second modifier ==
versionToComparable( testVersion ) =0000500100014.300 is this higher ?
second modifier ==
second modifier ==
isVersionHigher = true
---------------
baseVersion - 6.7.0
testVersion - 6.8-snapshot
versionToComparable( baseVersion ) =0000600070000.500
second modifier ==
versionToComparable( testVersion ) =0000600080000.100 is this higher ?
second modifier ==
isVersionHigher = true
---------------
baseVersion - 6.7.1
testVersion - 6.7.0-release
versionToComparable( baseVersion ) =0000600070001.500
second modifier ==
versionToComparable( testVersion ) =0000600070000.500 is this higher ?
second modifier ==
isVersionHigher = false
---------------
baseVersion - 6-snapshot
testVersion - 6.0.0-beta
second modifier ==
versionToComparable( baseVersion ) =0000600000000.100
second modifier ==
versionToComparable( testVersion ) =0000600000000.300 is this higher ?
second modifier ==
second modifier ==
isVersionHigher = true
---------------
baseVersion - 6.0-snapshot
testVersion - 6.0.0-whatthe
second modifier ==
versionToComparable( baseVersion ) =0000600000000.100
versionToComparable( testVersion ) =0000600000000.000 is this higher ?
second modifier ==
isVersionHigher = false
---------------
baseVersion - 5.10.12-Alpha-1
testVersion - 5.10.12-alpha-2
second modifier =-1=
versionToComparable( baseVersion ) =0000500100012.201
second modifier =-2=
versionToComparable( testVersion ) =0000500100012.202 is this higher ?
second modifier =-2=
second modifier =-1=
isVersionHigher = true
---------------
baseVersion - 5.10.13-release-1
testVersion - 5.10.13-release2
second modifier =-1=
versionToComparable( baseVersion ) =0000500100013.501
second modifier =2=
versionToComparable( testVersion ) =0000500100013.502 is this higher ?
second modifier =2=
second modifier =-1=
isVersionHigher = true
---------------
baseVersion - 10-rc42
testVersion - 10.0.0-rc53
second modifier =42=
versionToComparable( baseVersion ) =0001000000000.442
second modifier =53=
versionToComparable( testVersion ) =0001000000000.453 is this higher ?
second modifier =53=
second modifier =42=
isVersionHigher = true
---------------

Chapin

Answer 15

I wrote an Open Source Library called MgntUtils that has a utility that works with String versions. It correctly compares them, works with version ranges and so forth. Here is this library javadoc See methods TextUtils.comapreVersions(...). It has been heavily used and well tested. Here is the article that describes the library and where to get it. It is available as Maven artifact and on the github (with sources and JavaDoc)

Misreckon

Answer 16

Maybe someone will be interested in my solution:

class Version private constructor(private val versionString: String) : Comparable<Version> {

    private val major: Int by lazy { versionString.split(".")[0].toInt() }

    private val minor: Int by lazy { versionString.split(".")[1].toInt() }

    private val patch: Int by lazy {
        val splitArray = versionString.split(".")

        if (splitArray.size == 3)
            splitArray[2].toInt()
        else
            0
    }

    override fun compareTo(other: Version): Int {
        return when {
            major > other.major -> 1
            major < other.major -> -1
            minor > other.minor -> 1
            minor < other.minor -> -1
            patch > other.patch -> 1
            patch < other.patch -> -1
            else -> 0
        }
    }

    override fun equals(other: Any?): Boolean {
        if (other == null || other !is Version) return false
        return compareTo(other) == 0
    }

    override fun hashCode(): Int {
        return major * minor * patch
    }

    companion object {
        private fun doesContainsVersion(string: String): Boolean {
            val versionArray = string.split(".")

            return versionArray.size in 2..3
                    && versionArray[0].toIntOrNull() != null
                    && versionArray[1].toIntOrNull() != null
                    && (versionArray.size == 2 || versionArray[2].toIntOrNull() != null)
        }

        fun from(string: String): Version? {
            return if (doesContainsVersion(string)) {
                Version(string)
            } else {
                null
            }
        }
    }
}

Usage:

val version1 = Version.from("3.2")
val version2 = Version.from("3.2.1")
version1 <= version2

Pylorus

Answer 17

I created simple utility for comparing versions on Android platform using Semantic Versioning convention. So it works only for strings in format X.Y.Z (Major.Minor.Patch) where X, Y, and Z are non-negative integers. You can find it on my GitHub.

Method Version.compareVersions(String v1, String v2) compares two version strings. It returns 0 if the versions are equal, 1 if version v1 is before version v2, -1 if version v1 is after version v2, -2 if version format is invalid.

Arber

your GitHub link is not found – Hautevienne

Answer 18

for my projects I use my commons-version library https://github.com/raydac/commons-version it contains two auxiliary classes - to parse version (parsed version can be compared with another version object because it is comparable one) and VersionValidator which allows to check version for some expression like !=ide-1.1.1,>idea-1.3.4-SNAPSHOT;<1.2.3

Histoplasmosis

Answer 19

public int CompareVersions(String version1, String version2)
{
    String[] string1Vals = version1.split("\\.");
    String[] string2Vals = version2.split("\\.");

    int length = Math.max(string1Vals.length, string2Vals.length);

    for (int i = 0; i < length; i++)
    {
        Integer v1 = (i < string1Vals.length)?Integer.parseInt(string1Vals[i]):0;
        Integer v2 = (i < string2Vals.length)?Integer.parseInt(string2Vals[i]):0;

        //Making sure Version1 bigger than version2
        if (v1 > v2)
        {
            return 1;
        }
        //Making sure Version1 smaller than version2
        else if(v1 < v2)
        {
            return -1;
        }
    }

    //Both are equal
    return 0;
}

Smyrna

Answer 20

I have written a small Java/Android library for comparing version numbers: https://github.com/G00fY2/version-compare

What it basically does is this:

  public int compareVersions(String versionA, String versionB) {
    String[] versionTokensA = versionA.split("\\.");
    String[] versionTokensB = versionB.split("\\.");
    List<Integer> versionNumbersA = new ArrayList<>();
    List<Integer> versionNumbersB = new ArrayList<>();

    for (String versionToken : versionTokensA) {
      versionNumbersA.add(Integer.parseInt(versionToken));
    }
    for (String versionToken : versionTokensB) {
      versionNumbersB.add(Integer.parseInt(versionToken));
    }

    final int versionASize = versionNumbersA.size();
    final int versionBSize = versionNumbersB.size();
    int maxSize = Math.max(versionASize, versionBSize);

    for (int i = 0; i < maxSize; i++) {
      if ((i < versionASize ? versionNumbersA.get(i) : 0) > (i < versionBSize ? versionNumbersB.get(i) : 0)) {
        return 1;
      } else if ((i < versionASize ? versionNumbersA.get(i) : 0) < (i < versionBSize ? versionNumbersB.get(i) : 0)) {
        return -1;
      }
    }
    return 0;
  }

This snippet doesn't offer any error checks or handling. Beside that my library also supports suffixes like "1.2-rc" > "1.2-beta".

Mignon

Answer 21

Since no answer on this page handles mixed text well, I made my own version:

import java.util.regex.Matcher;
import java.util.regex.Pattern;

class Main {
    static double parseVersion(String v) {
        if (v.isEmpty()) {
            return 0;
        }
        Pattern p = Pattern.compile("^(\\D*)(\\d*)(\\D*)$");
        Matcher m = p.matcher(v);
        m.find();
        if (m.group(2).isEmpty()) {
            // v1.0.0.[preview]
            return -1;
        }
        double i = Integer.parseInt(m.group(2));
        if (!m.group(3).isEmpty()) {
            // v1.0.[0b]
            i -= 0.1;
        }
        return i;
    }

    public static int versionCompare(String str1, String str2) {
        String[] v1 = str1.split("\\.");
        String[] v2 = str2.split("\\.");
        int i = 0;
        for (; i < v1.length && i < v2.length; i++) {
            double iv1 = parseVersion(v1[i]);
            double iv2 = parseVersion(v2[i]);

            if (iv1 != iv2) {
                return iv1 - iv2 < 0 ? -1 : 1;
            }
        }
        if (i < v1.length) {
            // "1.0.1", "1.0"
            double iv1 = parseVersion(v1[i]);
            return iv1 < 0 ? -1 : (int) Math.ceil(iv1);
        }
        if (i < v2.length) {
            double iv2 = parseVersion(v2[i]);
            return -iv2 < 0 ? -1 : (int) Math.ceil(iv2);
        }
        return 0;
    }


    public static void main(String[] args) {
        System.out.println("versionCompare(v1.0.0, 1.0.0)");
        System.out.println(versionCompare("v1.0.0", "1.0.0")); // 0

        System.out.println("versionCompare(v1.0.0b, 1.0.0)");
        System.out.println(versionCompare("v1.0.0b", "1.0.0")); // -1

        System.out.println("versionCompare(v1.0.0.preview, 1.0.0)");
        System.out.println(versionCompare("v1.0.0.preview", "1.0.0")); // -1

        System.out.println("versionCompare(v1.0, 1.0.0)");
        System.out.println(versionCompare("v1.0", "1.0.0")); // 0

        System.out.println("versionCompare(ver1.0, 1.0.1)");
        System.out.println(versionCompare("ver1.0", "1.0.1")); // -1
    }
}

It still falls short on cases where you need to compare "alpha" with "beta" though.

Kriskrischer

Answer 22

based on https://mcmap.net/q/41886/-how-do-you-compare-two-version-strings-in-java

class Version(private val value: String) : Comparable<Version> {
    private val splitted by lazy { value.split("-").first().split(".").map { it.toIntOrNull() ?: 0 } }

    override fun compareTo(other: Version): Int {
        for (i in 0 until maxOf(splitted.size, other.splitted.size)) {
            val compare = splitted.getOrElse(i) { 0 }.compareTo(other.splitted.getOrElse(i) { 0 })
            if (compare != 0)
                return compare
        }
        return 0
    }
}

you can use like:

    System.err.println(Version("1.0").compareTo( Version("1.0")))
    System.err.println(Version("1.0") < Version("1.1"))
    System.err.println(Version("1.10") > Version("1.9"))
    System.err.println(Version("1.10.1") > Version("1.10"))
    System.err.println(Version("0.0.1") < Version("1"))

Heyday

Answer 23

Wrote a little function myself.Simpler Using Lists

 public static boolean checkVersionUpdate(String olderVerison, String newVersion) {
        if (olderVerison.length() == 0 || newVersion.length() == 0) {
            return false;
        }
        List<String> newVerList = Arrays.asList(newVersion.split("\\."));
        List<String> oldVerList = Arrays.asList(olderVerison.split("\\."));

        int diff = newVerList.size() - oldVerList.size();
        List<String> newList = new ArrayList<>();
        if (diff > 0) {
            newList.addAll(oldVerList);
            for (int i = 0; i < diff; i++) {
                newList.add("0");
            }
            return examineArray(newList, newVerList, diff);
        } else if (diff < 0) {
            newList.addAll(newVerList);
            for (int i = 0; i < -diff; i++) {
                newList.add("0");
            }
            return examineArray(oldVerList, newList, diff);
        } else {
            return examineArray(oldVerList, newVerList, diff);
        }

    }

    public static boolean examineArray(List<String> oldList, List<String> newList, int diff) {
        boolean newVersionGreater = false;
        for (int i = 0; i < oldList.size(); i++) {
            if (Integer.parseInt(newList.get(i)) > Integer.parseInt(oldList.get(i))) {
                newVersionGreater = true;
                break;
            } else if (Integer.parseInt(newList.get(i)) < Integer.parseInt(oldList.get(i))) {
                newVersionGreater = false;
                break;
            } else {
                newVersionGreater = diff > 0;
            }
        }

        return newVersionGreater;
    }

Metaxylem

Answer 24

Using Java 8 Stream to replace leading zeroes in components. This code passed all tests on interviewbit.com

public int compareVersion(String A, String B) {
    List<String> strList1 = Arrays.stream(A.split("\\."))
                                           .map(s -> s.replaceAll("^0+(?!$)", ""))
                                           .collect(Collectors.toList());
    List<String> strList2 = Arrays.stream(B.split("\\."))
                                           .map(s -> s.replaceAll("^0+(?!$)", ""))
                                           .collect(Collectors.toList());
    int len1 = strList1.size();
    int len2 = strList2.size();
    int i = 0;
    while(i < len1 && i < len2){
        if (strList1.get(i).length() > strList2.get(i).length()) return 1;
        if (strList1.get(i).length() < strList2.get(i).length()) return -1;
        int result = new Long(strList1.get(i)).compareTo(new Long(strList2.get(i)));
        if (result != 0) return result;
        i++;
    }
    while (i < len1){
        if (!strList1.get(i++).equals("0")) return 1;
    }
    while (i < len2){
        if (!strList2.get(i++).equals("0")) return -1;
    }
    return 0;
}

Seepage

Answer 25

For someone who is going to show Force Update Alert based on version number I have a following Idea. This may be used when comparing the versions between Android Current App version and firebase remote config version. This is not exactly the answer for the question asked but this will help someone definitely.

import java.util.List;
import java.util.ArrayList;
import java.util.Arrays;
public class Main
{
  static String firebaseVersion = "2.1.3"; // or 2.1
  static String appVersion = "2.1.4";
  static List<String> firebaseVersionArray;
  static List<String> appVersionArray;
  static boolean isNeedToShowAlert = false;
  public static void main (String[]args)
  {
    System.out.println ("Hello World");
    firebaseVersionArray = new ArrayList<String>(Arrays.asList(firebaseVersion.split ("\\.")));
    appVersionArray = new ArrayList<String>(Arrays.asList(appVersion.split ("\\.")));
    if(appVersionArray.size() < firebaseVersionArray.size()) {
        appVersionArray.add("0");
    }
    if(firebaseVersionArray.size() < appVersionArray.size()) {
        firebaseVersionArray.add("0");
    }
    isNeedToShowAlert = needToShowAlert(); //Returns false
    System.out.println (isNeedToShowAlert);

  }
  static boolean needToShowAlert() {
      boolean result = false;
      for(int i = 0 ; i < appVersionArray.size() ; i++) {
          if (Integer.parseInt(appVersionArray.get(i)) == Integer.parseInt(firebaseVersionArray.get(i))) {
              continue;
          } else if (Integer.parseInt(appVersionArray.get(i)) > Integer.parseInt(firebaseVersionArray.get(i))){
             result = false;
             break;
          } else if (Integer.parseInt(appVersionArray.get(i)) < Integer.parseInt(firebaseVersionArray.get(i))) {
             result = true;
             break;  
          }
      }
      return result;
  }
}

You can run this code by copy pasting in https://www.onlinegdb.com/online_java_compiler

Claro

Answer 26

public static void main(String[] args) {

    String version1 = "1.0";
    String version2 = "1.0.0";
    String[] version1_splits = version1.split("\\.");
    String[] version2_splits = version2.split("\\.");
    int length = version1_splits.length >= version2_splits.length ? version1_splits.length : version2_splits.length;
    int i=0;
    for(;i<length;i++){
        int version1_int = getValue(version1_splits,i);
        int version2_int = getValue(version2_splits,i);
        if(version1_int > version2_int){
            System.out.println("version1 > version2");
            break;
        }
        else if(version1_int < version2_int){
            System.out.println("version2 > version1");
            break;
        }
        else{
            if(i == length-1)
            System.out.println("version1 = version2");
        }
    }
}

private static int getValue(String[] version1_splits, int i) {
    int temp;
    try{
        temp = Integer.valueOf(version1_splits[i]);
    }
    catch(IndexOutOfBoundsException e){
        temp=0;
    }

    return temp;
}

Librarianship

Answer 27

kotlin:

@kotlin.jvm.Throws(InvalidParameterException::class)
fun String.versionCompare(remoteVersion: String?): Int {
    val remote = remoteVersion?.splitToSequence(".")?.toList() ?: return 1
    val local = this.splitToSequence(".").toList()

    if(local.filter { it.toIntOrNull() != null }.size != local.size) throw InvalidParameterException("version invalid: $this")
    if(remote.filter { it.toIntOrNull() != null }.size != remote.size) throw InvalidParameterException("version invalid: $remoteVersion")

    val totalRange = 0 until kotlin.math.max(local.size, remote.size)
    for (i in totalRange) {
        if (i < remote.size && i < local.size) {
            val result = local[i].compareTo(remote[i])
            if (result != 0) return result
        } else (
            return local.size.compareTo(remote.size)
        )
    }
    return 0
}

Tidal

Answer 28

In kotlin (another language of the JVM), here is my simple implementation of the Version class:

data class Version(val major: Int, val minor: Int = 0, val patch: Int = 0): Comparable<Version> {

    override fun compareTo(other: Version): Int {
        return when {
            major > other.major -> 1
            major < other.major -> -1
            minor > other.minor -> 1
            minor < other.minor -> -1
            patch > other.patch -> 1
            patch < other.patch -> -1
            else -> 0
        }
    }

    companion object {
        fun from(string: String): Version? {
            val versionArray = string.split(".")
            if (versionArray.size in 1..3 && versionArray.all { it.toIntOrNull() != null }) {
                val versionIntArray = (versionArray.map { it.toInt() } + listOf(0, 0)).zip(listOf(0, 0, 0), Int::plus)
                val (majorVersion, minorVersion, patchVersion) = versionIntArray.take(3)
                return Version(majorVersion, minorVersion, patchVersion)
            }
            return null
        }
    }
}

with the unit test:

@Test
fun version_sorting() {
    var versions = listOf(
        "1.0.2",
        "1.0.0",
        "1.0.1",
        "1.0.11",
        "1.1.0",
        "1.11.0",
        "0.0.1",
        "1.2.1",
        "2",
        "10",
    );
    versions.map {from(it) }.sortedBy { it }.map { println(it)}
}

Speciosity

1) the question is marked with the java tag (no other language), code posted in this answer is not Java; 2) the question is 15 years old, accepted, and has more than 30 answers – Habitue

Answer 29

You can use the versionparser library. It can parse versions and version constraints expressed in a number of versioning schemes (e.g. Maven, Semantic, NPM, etc.). The resulting version objects are ordered and the version constraint objects support set operations (e.g. intersection).

Arvonio

Answer 30

This code try to resolve this type of comparison versions.

Most of the version specifiers, like >= 1.0, are self-explanatory. The specifier ~> has a special meaning, best shown by example. ~> 2.0.3 is identical to >= 2.0.3 and < 2.1. ~> 2.1 is identical to >= 2.1 and < 3.0.

public static boolean apply(String cmpDeviceVersion, String reqDeviceVersion)
{
    Boolean equal           = !cmpDeviceVersion.contains(">") && !cmpDeviceVersion.contains(">=") &&
                              !cmpDeviceVersion.contains("<") && !cmpDeviceVersion.contains("<=") &&
                              !cmpDeviceVersion.contains("~>");

    Boolean between         = cmpDeviceVersion.contains("~>");
    Boolean higher          = cmpDeviceVersion.contains(">") && !cmpDeviceVersion.contains(">=") && !cmpDeviceVersion.contains("~>");
    Boolean higherOrEqual   = cmpDeviceVersion.contains(">=");

    Boolean less            = cmpDeviceVersion.contains("<") && !cmpDeviceVersion.contains("<=");
    Boolean lessOrEqual     = cmpDeviceVersion.contains("<=");

    cmpDeviceVersion        = cmpDeviceVersion.replaceAll("[<>=~]", "");
    cmpDeviceVersion        = cmpDeviceVersion.trim();

    String[] version        = cmpDeviceVersion.split("\\.");
    String[] reqVersion     = reqDeviceVersion.split("\\.");

    if(equal)
    {
        return isEqual(version, reqVersion);
    }
    else if(between)
    {
        return isBetween(version, reqVersion);
    }
    else if(higher)
    {
        return isHigher(version, reqVersion);
    }
    else if(higherOrEqual)
    {
        return isEqual(version, reqVersion) || isHigher(version, reqVersion);
    }
    else if(less)
    {
        return isLess(version, reqVersion);
    }
    else if(lessOrEqual)
    {
        return isEqual(version, reqVersion) || isLess(version, reqVersion);
    }

    return false;
}

private static boolean isEqual(String[] version, String[] reqVersion)
{
    String strVersion = StringUtils.join(version);
    String strReqVersion = StringUtils.join(reqVersion);
    if(version.length > reqVersion.length)
    {
        Integer diff = version.length - reqVersion.length;
        strReqVersion += StringUtils.repeat(".0", diff);
    }
    else if(reqVersion.length > version.length)
    {
        Integer diff = reqVersion.length - version.length;
        strVersion += StringUtils.repeat(".0", diff);
    }

    return strVersion.equals(strReqVersion);
}

private static boolean isHigher(String[] version, String[] reqVersion)
{
    String strVersion = StringUtils.join(version);
    String strReqVersion = StringUtils.join(reqVersion);
    if(version.length > reqVersion.length)
    {
        Integer diff = version.length - reqVersion.length;
        strReqVersion += StringUtils.repeat(".0", diff);
    }
    else if(reqVersion.length > version.length)
    {
        Integer diff = reqVersion.length - version.length;
        strVersion += StringUtils.repeat(".0", diff);
    }

    return strReqVersion.compareTo(strVersion) > 0;
}

private static boolean isLess(String[] version, String[] reqVersion)
{
    String strVersion = StringUtils.join(version);
    String strReqVersion = StringUtils.join(reqVersion);
    if(version.length > reqVersion.length)
    {
        Integer diff = version.length - reqVersion.length;
        strReqVersion += StringUtils.repeat(".0", diff);
    }
    else if(reqVersion.length > version.length)
    {
        Integer diff = reqVersion.length - version.length;
        strVersion += StringUtils.repeat(".0", diff);
    }

    return strReqVersion.compareTo(strVersion) < 0;
}

private static boolean isBetween(String[] version, String[] reqVersion)
{
    return (isEqual(version, reqVersion) || isHigher(version, reqVersion)) &&
            isLess(getNextVersion(version), reqVersion);
}

private static String[] getNextVersion(String[] version)
{
    String[] nextVersion = new String[version.length];
    for(int i = version.length - 1; i >= 0 ; i--)
    {
        if(i == version.length - 1)
        {
            nextVersion[i] = "0";
        }
        else if((i == version.length - 2) && NumberUtils.isNumber(version[i]))
        {
            nextVersion[i] = String.valueOf(NumberUtils.toInt(version[i]) + 1);
        }
        else
        {
            nextVersion[i] = version[i];
        }
    }
    return nextVersion;
}

Sanction

Answer 31

I liked the idea from @Peter Lawrey, And i extended it to further limits :

    /**
    * Normalize string array, 
    * Appends zeros if string from the array
    * has length smaller than the maxLen.
    **/
    private String normalize(String[] split, int maxLen){
        StringBuilder sb = new StringBuilder("");
        for(String s : split) {
            for(int i = 0; i<maxLen-s.length(); i++) sb.append('0');
            sb.append(s);
        }
        return sb.toString();
    }

    /**
    * Removes trailing zeros of the form '.00.0...00'
    * (and does not remove zeros from, say, '4.1.100')
    **/
    public String removeTrailingZeros(String s){
        int i = s.length()-1;
        int k = s.length()-1;
        while(i >= 0 && (s.charAt(i) == '.' || s.charAt(i) == '0')){
          if(s.charAt(i) == '.') k = i-1;
          i--;  
        } 
        return s.substring(0,k+1);
    }

    /**
    * Compares two versions(works for alphabets too),
    * Returns 1 if v1 > v2, returns 0 if v1 == v2,
    * and returns -1 if v1 < v2.
    **/
    public int compareVersion(String v1, String v2) {

        // Uncomment below two lines if for you, say, 4.1.0 is equal to 4.1
        // v1 = removeTrailingZeros(v1);
        // v2 = removeTrailingZeros(v2);

        String[] splitv1 = v1.split("\\.");
        String[] splitv2 = v2.split("\\.");
        int maxLen = 0;
        for(String str : splitv1) maxLen = Math.max(maxLen, str.length());
        for(String str : splitv2) maxLen = Math.max(maxLen, str.length());
        int cmp = normalize(splitv1, maxLen).compareTo(normalize(splitv2, maxLen));
        return cmp > 0 ? 1 : (cmp < 0 ? -1 : 0);
    }

Hope it helps someone. It passed all test cases in interviewbit and leetcode (need to uncomment two lines in compareVersion function).

Easily tested !

Chloropicrin

Answer 32

public class VersionComparator {

    /* loop through both version strings
     * then loop through the inner string to computer the val of the int
     * for each integer read, do num*10+<integer read>
     * and stop when stumbling upon '.'
     * When '.' is encountered...
     * see if '.' is encountered for both strings
     * if it is then compare num1 and num2 
     * if num1 == num2... iterate over p1++, p2++
     * else return (num1 > num2) ? 1 : -1
     * If both the string end then compare(num1, num2) return 0, 1, -1
     * else loop through the longer string and 
     * verify if it only has trailing zeros
     * If it only has trailing zeros then return 0
     * else it is greater than the other string
     */
    public static int compareVersions(String v1, String v2) {
        int num1 = 0;
        int num2 = 0;
        int p1 = 0;
        int p2 = 0;

        while (p1 < v1.length() && p2 < v2.length()) {
            num1 = Integer.parseInt(v1.charAt(p1) + "");
            num2 = Integer.parseInt(v2.charAt(p2) + "");
            p1++;
            p2++;

            while (p1 < v1.length() && p2 < v2.length() && v1.charAt(p1) != '.' && v2.charAt(p2) != '.') {
                if (p1 < v1.length()) num1 = num1 * 10 + Integer.parseInt(v1.charAt(p1) + "");
                if (p2 < v2.length()) num2 = num2 * 10 + Integer.parseInt(v2.charAt(p2) + "");
                p1++;
                p2++;
            }

            if (p1 < v1.length() && p2 < v2.length() && v1.charAt(p1) == '.' && v2.charAt(p2) == '.') {
                if ((num1 ^ num2) == 0) {
                    p1++;
                    p2++;
                }
                else return (num1 > num2) ? 1 : -1;
            }
            else if (p1 < v1.length() && p2 < v2.length() && v1.charAt(p1) == '.') return -1;
            else if (p1 < v1.length() && p2 < v2.length() && v2.charAt(p2) == '.') return 1;
        }

        if (p1 == v1.length() && p2 == v2.length()) {
            if ((num1 ^ num2) == 0) return 0;
            else return (num1 > num2) ? 1 : -1;
        }
        else if (p1 == v1.length()) {
            if ((num1 ^ num2) == 0) {
                while (p2 < v2.length()) {
                    if (v2.charAt(p2) != '.' && v2.charAt(p2) != '0') return -1;
                    p2++;
                }
                return 0;
            }
            else return (num1 > num2) ? 1 : -1;
        }
        else {
            if ((num1 ^ num2) == 0) {
                while (p1 < v1.length()) {
                    if (v1.charAt(p1) != '.' && v1.charAt(p1) != '0') return 1;
                    p1++;
                }
                return 0;
            }
            else return (num1 > num2) ? 1 : -1;
        }
    }

    public static void main(String[] args) {
        System.out.println(compareVersions("11.23", "11.21.1.0.0.1.0") ^ 1);
        System.out.println(compareVersions("11.21.1.0.0.1.0", "11.23") ^ -1);
        System.out.println(compareVersions("11.23", "11.23.0.0.0.1.0") ^ -1);
        System.out.println(compareVersions("11.2", "11.23") ^ -1);
        System.out.println(compareVersions("11.23", "11.21.1.0.0.1.0") ^ 1);
        System.out.println(compareVersions("1.21.1.0.0.1.0", "2.23") ^ -1);
        System.out.println(compareVersions("11.23", "11.21.1.0.0.1.0") ^ 1);
        System.out.println(compareVersions("11.23.0.0.0.0.0", "11.23") ^ 0);
        System.out.println(compareVersions("11.23", "11.21.1.0.0.1.0") ^ 1);
        System.out.println(compareVersions("1.5.1.3", "1.5.1.3.0") ^ 0);
        System.out.println(compareVersions("1.5.1.4", "1.5.1.3.0") ^ 1);
        System.out.println(compareVersions("1.2.1.3", "1.5.1.3.0") ^ -1);
        System.out.println(compareVersions("1.2.1.3", "1.22.1.3.0") ^ -1);
        System.out.println(compareVersions("1.222.1.3", "1.22.1.3.0") ^ 1);
    }
}

Emmie

Answer 33

Here's an optimized implementation:

public static final Comparator<CharSequence> VERSION_ORDER = new Comparator<CharSequence>() {

  @Override
  public int compare (CharSequence lhs, CharSequence rhs) {
    int ll = lhs.length(), rl = rhs.length(), lv = 0, rv = 0, li = 0, ri = 0;
    char c;
    do {
      lv = rv = 0;
      while (--ll >= 0) {
        c = lhs.charAt(li++);
        if (c < '0' || c > '9')
          break;
        lv = lv*10 + c - '0';
      }
      while (--rl >= 0) {
        c = rhs.charAt(ri++);
        if (c < '0' || c > '9')
          break;
        rv = rv*10 + c - '0';
      }
    } while (lv == rv && (ll >= 0 || rl >= 0));
    return lv - rv;
  }

};

Result:

"0.1" - "1.0" = -1
"1.0" - "1.0" = 0
"1.0" - "1.0.0" = 0
"10" - "1.0" = 9
"3.7.6" - "3.7.11" = -5
"foobar" - "1.0" = -1

Beadle