Bundled Modules Reference

May 27, 2026 · View on GitHub

PerlOnJava ships with 150+ modules built into the JAR — no installation needed. Additional pure-Perl modules can be installed from CPAN with jcpan.

This page lists every bundled module, grouped by category, and documents modules that have external requirements or special instructions.

Modules with External Requirements

Some bundled modules need external software to be installed separately.

DBI — Database Access

DBI is bundled with a JDBC backend. SQLite works out of the box (the driver is included in the JAR). Other databases require adding a JDBC driver.

use DBI;
my $dbh = DBI->connect("dbi:SQLite:dbname=:memory:", "", "");

For MySQL, PostgreSQL, Oracle, BigQuery, and other databases, see the full guide: Database Access Guide.

Database	Driver setup
SQLite	Built-in — nothing to install
MySQL	`./jperl Configure.pl --search mysql-connector-java`
PostgreSQL	`./jperl Configure.pl --search postgresql`
Oracle	`./jperl Configure.pl --search ojdbc`

Image::Magick — Image Processing

Image::Magick is a pure-Perl CLI wrapper that delegates to ImageMagick command-line tools. It provides the same API as the CPAN XS module (Read, Write, Resize, Crop, Annotate, etc.) without requiring native PerlMagick bindings.

Requires ImageMagick CLI tools to be installed and in PATH.

# macOS
brew install imagemagick

# Ubuntu / Debian
sudo apt install imagemagick

# Windows
choco install imagemagick

ImageMagick 7 (magick command) is preferred. ImageMagick 6 (convert/identify) is also supported on Linux and macOS.

use Image::Magick;
my $img = Image::Magick->new;
$img->Set(size => '200x200');
$img->Read('xc:white');
$img->Resize(geometry => '100x100');
$img->Write('output.png');

See the design document for implementation details: dev/modules/image_magick.md.

Plack::Handler::Netty — Web Server

Plack::Handler::Netty provides a PSGI-compliant web server using Netty's async I/O. Supports HTTP/HTTPS, streaming responses, and runs any PSGI application.

use Plack::Handler::Netty;

my $app = sub {
    my ($env) = @_;
    return [200, ['Content-Type' => 'text/plain'], ['Hello!']];
};

my $handler = Plack::Handler::Netty->new(port => 5000);
$handler->run($app);

Performance: 32,000+ req/sec for simple responses. See full documentation: examples/http_server_plack/README.md.

Moose / Class::MOP

PerlOnJava bundles upstream Moose 2.4000 in the JAR — use Moose; works out of the box, no extra install needed.

use Moose;

has name => (is => 'ro', isa => 'Str', required => 1);
has age  => (is => 'rw', isa => 'Int', default  => 0);

__PACKAGE__->meta->make_immutable;

Status

The bundled stack passes the bulk of the upstream test suites:

Suite	Files	Asserts	Result
Moose 2.4000 own tests	≥396/478	≥13413/13550 (~99%)	Mostly green
DBIx::Class 0.082843 (depends on `Moo`; both installed via `jcpan`)	314/314	13858/13858	PASS

Run the full Moose test suite locally with:

./jcpan -t Moose

DBIx::Class itself depends on Moo, not Moose. Both are pure-Perl modules — jcpan will install them from CPAN before running the test suite:

./jcpan -t DBIx::Class

Known limitations

The remaining ~80 failing test files cluster around features that are deliberately out of scope or genuinely unimplemented:

threads / fork — PerlOnJava has neither. The handful of tests that exercise share, lock, or fork-based DEMOLISH timing cannot pass and are expected to fail.
Numeric warning messages (Argument "x" isn't numeric in addition) — PerlOnJava does not emit these specific warning categories yet.
Stack-trace shape — frames inside generated method modifiers may stringify as __ANON__ rather than Pkg::method.
Moose::Exception attributes named INC — attribute name collision with the @INC global.
Anonymous metaclass GC timing — depends on the JVM's reachability walker scheduler; deterministic only for hierarchies in the Class::MOP / Moose / Moo class set.
Native trait Hash coerce + delete — corner cases in the generated coercion path.

For the up-to-date list and design rationale, see dev/modules/moose_support.md.

Performance

The bundled Moose stack runs the DBIx::Class test suite in ~29 minutes on this hardware (single-job mode). No formal comparison to CPAN-Perl + XS is published yet.

Module Categories

Core / Pragmas

These are loaded automatically or via use:

Module	Implementation	Notes
`strict`	Java
`warnings`	Java
`utf8`	Java
`feature`	Java
`integer`	Java
`bytes`	Java
`lib`	Java
`base`	Java
`parent`	Java
`vars`	Java
`subs`	Java
`attributes`	Java
`overload`	Java + Perl
`overloading`	Java
`re`	Java
`mro`	Java
`builtin`	Java
`version`	Java + Perl
`Exporter`	Perl
`AutoLoader`	Perl
`English`	Perl
`Env`	Perl
`Fatal`	Perl
`Config`	Perl
`Errno`	Perl
`Fcntl`	Perl
`B`	Perl	Partial — enough for B::Deparse
`UNIVERSAL`	Java	`isa`, `can`, `DOES`, `VERSION`

Data Processing

Module	Implementation	Notes
`Data::Dumper`	Java + Perl
`JSON` / `JSON::PP`	Perl	`JSON` delegates to the bundled pure-Perl `JSON::PP`
`Cpanel::JSON::XS` (+ `::Type`, `::Boolean`)	Perl	Same encoder/decoder as `JSON::PP`; XS-only type-aware `encode_json` / `decode_json` arguments are not supported
`YAML::PP`	Java + Perl
`TOML`	Java
`Text::CSV`	Java
`Storable`	Java + Perl	`freeze`, `thaw`, `dclone`, `store`, `retrieve`, `nstore`, `nfreeze` — produces and consumes the native Perl `pst0` binary format, interoperable with system perl in both directions. See `dev/modules/storable_binary_format.md`.
`Clone`	Java + Perl	Deep copy
`Scalar::Util`	Java	`blessed`, `reftype`, `weaken`, `dualvar`, etc.
`List::Util`	Java	`reduce`, `first`, `min`, `max`, `sum`, `mesh`/`zip`, etc.
`Hash::Util`	Java	`lock_keys`, `lock_hash`, etc.

File & I/O

Module	Implementation	Notes
`File::Spec`	Java + Perl	Platform-specific variants included
`File::Basename`	Perl
`File::Copy`	Perl
`File::Find`	Perl
`File::Glob`	Perl
`File::Path`	Perl	`make_path`, `remove_tree`
`File::Temp`	Java + Perl
`File::stat`	Perl
`File::Compare`	Perl
`Cwd`	Java
`IO::File`	Perl
`IO::Handle`	Java + Perl
`IO::Dir`	Perl
`IO::Select`	Perl
`IO::Seekable`	Perl
`IO::Zlib`	Perl
`FileHandle`	Perl
`DirHandle`	Perl
`SelectSaver`	Perl
`PerlIO::encoding`	Perl

Network & Web

Module	Implementation	Notes
`HTTP::Tiny`	Java + Perl	Java `HttpClient` backend
`HTTP::Date`	Perl
`HTTP::CookieJar`	Perl
`Socket`	Java + Perl
`IO::Socket::INET`	Perl
`IO::Socket::IP`	Perl
`IO::Socket::UNIX`	Perl
`IO::Socket::SSL`	Java + Perl	Uses JVM TLS (JSSE) — no OpenSSL needed
`Net::SSLeay`	Java + Perl	Uses JVM TLS (JSSE) — no OpenSSL needed
`Net::FTP`	Perl
`Net::SMTP`	Perl
`Net::POP3`	Perl
`Net::NNTP`	Perl
`Net::Ping`	Perl
`Net::Cmd`	Perl
`URI::Escape`	Perl

Database

Module	Implementation	Notes
`DBI`	Java + Perl	JDBC backend; see Database Access
`DBD::SQLite`	Perl	Built-in — no driver setup needed
`DBD::Mem`	Perl	In-memory tables

Cryptography & Encoding

Module	Implementation	Notes
`Digest::MD5`	Java	`java.security.MessageDigest`
`Digest::SHA`	Java	`java.security.MessageDigest`
`Digest`	Perl
`MIME::Base64`	Java
`MIME::QuotedPrint`	Java
`Encode`	Java + Perl
`Unicode::Normalize`	Java
`Unicode::UCD`	Java

Archives & Compression

Module	Implementation	Notes
`Archive::Tar`	Perl
`Archive::Zip`	Java + Perl	Uses `java.util.zip`
`Compress::Bzip2`	Java + Perl	Uses Apache Commons Compress
`Compress::Raw::Bzip2`	Java + Perl	Uses Apache Commons Compress
`Compress::Raw::Zlib`	Java	Uses `java.util.zip`
`Compress::Zlib`	Java + Perl
`IO::Zlib`	Perl

XML & HTML

Module	Implementation	Notes
`XML::Parser`	Perl
`XML::Parser::Expat`	Java	Uses Java SAX parser
`HTML::Parser`	Java

Image Processing

Module	Implementation	Notes
`Image::Magick`	Perl	CLI wrapper; requires `magick` in PATH

Date & Time

Module	Implementation	Notes
`Time::HiRes`	Java	`System.nanoTime()`
`Time::Piece`	Java + Perl
`Time::Local`	Perl
`DateTime`	Java + Perl	Java backend bundled; install `DateTime` from CPAN with `jcpan -i DateTime` (timezone data gets frequent updates)
`POSIX`	Java	Includes `strftime`, `mktime`, etc.

Math

Module	Implementation	Notes
`Math::BigInt`	Java	Uses `java.math.BigInteger`

Process Control

Module	Implementation	Notes
`IPC::Open2`	Perl
`IPC::Open3`	Java
`IPC::System::Simple`	Perl

Terminal

Module	Implementation	Notes
`Term::ReadKey`	Java
`Term::ReadLine`	Java
`Term::ANSIColor`	Perl
`Term::Table`	Perl
`IO::Tty`	Java + Perl	PTY allocation, terminal constants, winsize ops via FFM
`IO::Pty`	Perl	Pseudo-terminal pairs; depends on IO::Tty
`IO::Tty::Constant`	Java + Perl	Terminal ioctl constants (TIOCGWINSZ, etc.)

OOP & Introspection

Module	Implementation	Notes
`Scalar::Util`	Java
`Sub::Name`	Java
`Sub::Util`	Java
`Class::Struct`	Perl
`Attribute::Handlers`	Perl
`Devel::Cycle`	Perl
`Devel::Peek`	Perl
`Class::XSAccessor` / `Class::XSAccessor::Array`	Perl	Pure-Perl replacement for the CPAN XS accessors; no entersub optimizer
`Class::MOP`	Perl	Upstream 2.4000 source
`Moose`	Perl	Upstream 2.4000 source; ~99% of upstream tests pass (no threads). See note below.
`B`	Perl	`svref_2object`, `B::CV`/`GV`/`STASH`, `CVf_ANON`, etc. — enough for `Class::MOP::get_code_info` and `B::Deparse`.

Testing

Module	Implementation	Notes
`Test::More`	Perl
`Test::Simple`	Perl
`Test::Builder`	Perl
`Test::Harness`	Perl
`Test2::Suite`	Perl	Full Test2 stack (~100 files)
`TAP::Harness`	Perl	Full TAP stack (~43 files)
`App::Prove`	Perl	`prove` command

Build & Install

Module	Implementation	Notes
`ExtUtils::MakeMaker`	Perl	PerlOnJava-specific version
`CPAN`	Perl	Full CPAN client (~30 sub-modules)
`CPAN::Meta`	Perl
`Module::Build::Base`	Perl
`Parse::CPAN::Meta`	Perl
`DynaLoader` / `XSLoader`	Java	Routes XS loads to Java implementations

Documentation

Module	Implementation	Notes
`Pod::Simple`	Perl	~22 sub-modules
`Pod::Perldoc`	Perl	~12 sub-modules
`Pod::Text`	Perl	+ Color, Overstrike, Termcap
`Pod::Man`	Perl
`Pod::Usage`	Perl
`Pod::Checker`	Perl
`Pod::Html`	Perl	+ `Pod::Html::Util`; `pod2html` POD-to-HTML converter

Java Integration

Module	Implementation	Notes
`Java::System`	Java + Perl	Access JVM system properties

Miscellaneous

Module	Implementation	Notes
`Getopt::Long`	Perl
`Getopt::Std`	Perl
`Sys::Hostname`	Java
`I18N::Langinfo`	Java
`Benchmark`	Perl
`Filter::Simple`	Perl
`Filter::Util::Call`	Java
`Tie::Hash` / `Tie::Array` / `Tie::Scalar`	Perl
`Tie::RefHash`	Perl

Implementation Types

Java — Core functionality implemented in Java for performance or JVM integration. These are in src/main/java/org/perlonjava/runtime/perlmodule/.
Perl — Pure-Perl module bundled in the JAR (src/main/perl/lib/).
Java + Perl — Java provides the XS-equivalent functions; a Perl .pm file provides the high-level API.

Adding a New Bundled Module

To bundle a new module into PerlOnJava, see the Module Porting Guide. After adding the module, update this page — add an entry to the appropriate category table with the module name, implementation type, and any notes about external requirements.