Java API Compliance Checker

Java API Compliance Checker (Java ACC) is a tool for checking backward binary and source-level compatibility of a Java library API. The tool checks classes declarations of old and new versions and analyzes changes that may break compatibility: removed methods, removed class fields, added abstract methods, etc. Binary incompatibility may result in crashing or incorrect behavior of existing clients built with an old version of a library when they are running with a new one. Source incompatibility may result in recompilation errors with a new library version. The tool is intended for library developers and operating system maintainers who are interested in ensuring backward compatibility, i.e. allow old clients to run or to be recompiled with newer library versions.

Downloads

Releases

All releases can be downloaded from this page or github.com.

Latest release: 1.1.1

Git

Read-only access to the latest development version:
git clone git://github.com/lvc/japi-compliance-checker.git

SVN (obsolete)

Read-only access to the latest development version:
svn co http://forge.ispras.ru/svn/java-api-compliance-checker

License

This program is free software. You may use, redistribute and/or modify it under the terms of either the GNU GPL or LGPL.

Supported Platforms

GNU/Linux, FreeBSD, Mac OS X, MS Windows (Xp, Vista, 7).

System Requirements

Linux, FreeBSD, Mac OS X
- JDK (javap, javac)
- Perl (5.8 or newer)

MS Windows
- JDK (javap, javac)
- Active Perl (5.8 or newer)

Detectable Compatibility Problems

The tool searches for the following list of changes in the API that may break binary/source-level compatibility. See “Evolving Java-based APIs: Achieving API Binary Compatibility” and this list of articles for more info.

Problems with Data Types
- Classes and Interfaces
  - removed classes or interfaces
  - removed fields
  - removed methods
  - change of a field type
  - change of a field access level
  - change of a field attributes (final, static, etc.)
  - change of a constant field value
  - changes in fields (recursive analysis)
  - added/removed abstract methods
  - added/removed super-interfaces
- Classes
  - added/removed super-classes
  - moving a method up class hierarchy
  - overridden methods
Problems with Methods
- changed attributes (static, final, synchronized, abstract, etc.)
- changed access level
- added/removed exceptions
Problems with Implementation
- changes in decompiled binary code

You can see detailed problem descriptions in the visual interactive HTML-format compatibility report (see this example) generated by the tool.

Limitations

The tool cannot check compatibility problems related to changes in code annotations.

Installation

The tool is ready-to-use after extracting the archive. You can also use a Makefile to install the tool into the system:
cd japi-compliance-checker-x.y.z/

sudo perl Makefile.pl -install --prefix=PREFIX [/usr, /usr/local, ...]

This command will install a japi-compliance-checker program in the PREFIX/bin system directory.

Usage

Compare Java ARchives

Command to compare two java archives:
japi-compliance-checker -l <library_name> -old <v1.jar> -new <v2.jar>

The compatibility report will be generated to:
compat_reports/<library_name>/<v1>_to_<v2>/compat_report.html

Compare Libraries

To compare different versions of a library that consists of many JARs you should create XML descriptors for two library versions: v1.xml and v2.xml files. Library descriptor is a simple XML-file that specifies version number, paths to Java ARchives and other optional information. An example of the descriptor is the following (1.0.xml):

 <version>
     1.0
 </version>
 
 <archives>
     /path1/to/JAR(s)/
     /path2/to/JAR(s)/
       ...
 </archives>

Command to compare two versions of a library:
japi-compliance-checker -l <library_name> -old <v1.xml> -new <v2.xml>

The compatibility report will be generated to:
compat_reports/<library_name>/<v1>_to_<v2>/compat_report.html

Check Clients Portability

Command to check a client portability to a newer version of a Java library API:
japi-compliance-checker -l <library_name> -old <v1.xml> -new <v2.xml> -client <client.jar>

Dump Library API to TXT file

Command to dump a Java library API to gzipped TXT format file:
japi-compliance-checker -l <library_name> -dump <some_version.xml>

The API dump will be generated to:
api_dumps/<library_name>/<library_name>_<some_version>.api.tar.gz

Command-Line Options

See the list of all options on this page.

Examples

Check the JDO library API versions for compatibility:
   japi-compliance-checker -l jdo -old jdo-api-2.0.jar -new jdo-api-3.0.jar

The report will be generated to:
   compat_reports/jdo/2.0_to_3.0/compat_report.html

Dump library API:
   japi-compliance-checker -l jdo -dump jdo-api-2.0.jar

The API dump will be generated to:
   api_dumps/jdo/jdo_2.0.api.tar.gz

Check client application portability between JDO versions:
   japi-compliance-checker -l jdo -old jdo-api-2.0.jar -new jdo-api-3.0.jar -client Teller.jar

Report Format

The HTML-format compatibility report consists of:

Test Info - The library name and compared version numbers.
Summary - Verdict on compatibility. Number of archives, classes and methods checked by the tool.
Problem Summary - Classification of compatibility problems.
Added Methods - The list of added methods.
Removed Methods - The list of removed methods.
Problems with Data Types - List of compatibility problems caused by changes in data types (divided by the severity level: High, Medium, Low). List of affected methods.
Problems with Methods - The list of compatibility problems caused by changes in method parameters and attributes (divided by the severity level).
Other Changes in Data Types - The list of compatible changes in data types;
Other Changes in Methods - The list of compatible changes in methods;
Problems with Implementation - The list of changes in decompiled binary code. Use -check-implementation option to enable this section.

Examples:

JDO: 2.2 to 3.0 compatibility report

Verdict on Compatibility

If the tool detected problems with high or medium level of severity or at least one removed method then the compatibility verdict is incompatible (otherwise compatible). Low-severity problems can be considered as warnings and don't affect the compatibility verdict unless the -strict option is specified.

Error Codes

Code	Meaning
0	Compatible. The tool has run without any errors.
1	Incompatible. The tool has run without any errors.
2	Common error code (undifferentiated).
3	A system command is not found.
4	Cannot access input files.
7	Invalid input ABI dump.
8	Unsupported version of input ABI dump.
9	Cannot find a module.

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Maintainers

The tool was initially developed by the Russian Linux Verification Center at ISPRAS and is now developed by ROSA Laboratory in Russia. Andrey Ponomarenko is the leader of this project.