Please note this project has been retired in favour of https://javaalmanac.io/jdk/21/.

This project creates a report of all API changes between two different JDK versions, using JapiCmp. You can use this tool for instance to compare OpenJDK 9 and OpenJDK 10, OpenJDK 9 and Oracle JDK 9 etc.

Example reports created by this generator can be found in the docs directory:

• API comparison of OpenJDK 8u301 and OpenJDK 9.4.0: jdk8-jdk9-api-diff.html
• API comparison of OpenJDK 9.0.4 and OpenJDK 10-b46: jdk9-jdk10-api-diff.html
• API comparison of OpenJDK 10.0.2 and OpenJDK 11+28: jdk10-jdk11-api-diff.html
• API comparison of OpenJDK 11.0.1+13 and OpenJDK 12-ea+27: jdk11-jdk12-api-diff.html
• API comparison of OpenJDK 12.0.1 and OpenJDK 13-ea+25: jdk12-jdk13-api-diff.html
• API comparison of OpenJDK 13.0.2 and OpenJDK 14.0.1: jdk13-jdk14-api-diff.html
• API comparison of OpenJDK 14.0.1 and OpenJDK 15-ea+27: jdk14-jdk15-api-diff.html
• API comparison of OpenJDK 15.0.2 and OpenJDK 16.0.1: jdk15-jdk16-api-diff.html
• API comparison of OpenJDK 16.0.1 and OpenJDK 17+35: jdk16-jdk17-api-diff.html
• API comparison of OpenJDK 17.0.0 and OpenJDK 18-ea+18-1093 jdk17-jdk18-api-diff.html

• API comparison of OpenJDK 8u301 and OpenJDK 11.0.11: jdk8-jdk11-api-diff.html
• API comparison of OpenJDK 11.0.11 and OpenJDK 17+35: jdk11-jdk17-api-diff.html

• API comparison of OpenJDK 8u301 and OpenJDK 17+35: jdk8-jdk17-api-diff.html

Some of them are huge, so loading may take a bit.

To create reports yourself, e.g. with different settings, run mvn clean install. The API change report can be found at target/jdk-api-diff.html.

Maven Toolchains are used to locate the JDKs to compare. There must be a toolchain entry of type jdk for each JDK to compare. Provide a file ~.m2/toolchains.xml like this:

<?xml version="1.0" encoding="UTF8"?>
<toolchains>
    <toolchain>
        <type>jdk</type>
        <provides>
            <version>9</version>
            <vendor>openjdk</vendor>
        </provides>
        <configuration>
            <jdkHome>/path/to/jdk-9</jdkHome>
        </configuration>
    </toolchain>
    <toolchain>
        <type>jdk</type>
        <provides>
            <version>10</version>
            <vendor>openjdk</vendor>
        </provides>
        <configuration>
            <jdkHome>/path/to/jdk-10</jdkHome>
        </configuration>
    </toolchain>
</toolchains>

Specify two properties, jdk1 and jdk2 in your pom.xml, identifying the base and target JDK version for the comparison. The values are comma-separated requirements matched against the <provides> configurations of the existing toolchain entries. Both properties must unambiguously identify one toolchain, for example:

<jdk1>version=9,vendor=openjdk</jdk1>
<jdk2>version=10,vendor=openjdk</jdk2>

If there's no matching toolchain or multiple ones match the given requirements, an exception will be raised.

The report is created via the ModuleRepackager class which is executed with the Maven exec plug-in. Adjust the following options passed to that class in pom.xml as needed:

• --exported-packages-only: true or false, depending on whether only exported packages should be compared or all packages; only applies if both compared versions are Java 9 or later
• --excluded-packages: a comma-separated listed of package names which should be excluded from the comparison; this can be useful to exclude unsupported packages such as com.apple or to ignore packages missing from Oracle EA builds but present in final versions such as jdk.management.jfr

This project is licensed under the Apache License version 2.0.