Bundled Modules Reference

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.

Recent CPAN compatibility additions include:

Module	Implementation	Notes
`JSON::DWIW`	Pure Perl over bundled `JSON::PP`	Relaxed legacy JSON API, file conversion, booleans, and compatibility helpers
`Taint::Runtime`	Perl + Java XS bridge	Runtime taint toggling and scalar taint inspection
`String::Similarity`	Java XS bridge	Unicode-aware `fstrcmp`/`similarity` implementation
`Socket6`	Pure Perl over Java-backed `Socket`	Legacy Socket6 flat-result API and IPv6 sockaddr helpers
`Email::Address::XS`	Pure Perl compatibility subset	Address parsing/object API used by `Email::Sender`
`Want`	Pure Perl compatibility subset	Non-lvalue predicates used by `JSONP`; full op-tree introspection is not yet available
`Net::Gen`	Java XS bridge	Net-ext constants and sockaddr helpers used by `Net::UDP`
`PadWalker`	Perl facade over Java runtime metadata	`peek_sub`, `closed_over`, and `set_closed_over`; caller-pad APIs remain unsupported
`Devel::Caller`	Perl facade over Java call frames	`caller_cv` and caller argument compatibility used by lexical tooling
`Devel::LexAlias`	Perl facade over Java lexical cells	Rebinds local and captured scalar, array, and hash lexicals
`Encode::Locale`	Pure Perl facade over bundled locale support	Provides LWP and XML::Parser with locale encoding aliases; includes `Encode::Alias`
`Crypt::Twofish2`	Java XS bridge	BouncyCastle Twofish engine with ECB, CBC, and CFB1 compatibility
`Crypt::Blowfish`	Java XS bridge	BouncyCastle Blowfish engine used by `Crypt::CBC` and `Git::Crypt`
`Proc::ProcessTable`	Perl + Java XS bridge	Portable process enumeration and common fields via Java `ProcessHandle`
`Tie::Array::Packed`	Perl + Java XS bridge	Packed scalar storage for the upstream tied-array API and pack formats
`Digest::JHash`	Java XS bridge	Jenkins 32-bit hash used by CHI and TimeZone::TimeZoneDB
`B::Flags`	Pure Perl over portable `B` objects	Named OP/SV flags without access to Perl C structures
`Data::Util`	Java XS bridge plus upstream pure-Perl fallback	Scalar classification preserves XS non-vivifying behavior; the remaining API uses `Data::Util::PurePerl`
`YAML::Syck`	Pure Perl over bundled `YAML::PP`	Compatibility loader/dumper for distributions that use the legacy Syck API
`Authen::PAM`	Java XS compatibility bridge	Constants and load-time API for PAM consumers; native conversations currently return `PAM_SYSTEM_ERR` rather than authenticating
`Text::Markdown::Hoedown`	Perl + Java XS bridge over commonmark-java	Hoedown-compatible HTML, table-of-contents, extension flags, and callback rendering without the native C library

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	`./Configure.pl --search mysql-connector-java`
PostgreSQL	`./Configure.pl --search postgresql`
Oracle	`./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:

Thread/fork-specific Moose tests — PerlOnJava now supports the documented ithread and threads::shared tranche, including share and lock, but the upstream Moose thread files have not all been promoted to the compatibility gate. True fork and fork-based DEMOLISH timing remain unsupported.
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.
`Scalar::Type`	Java + Perl	Scalar storage-type introspection without native XS
`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
`Crypt::Twofish2`	Java + Perl	Uses the bundled BouncyCastle provider; passes all 83 upstream vectors
`MIME::Base64`	Java
`MIME::QuotedPrint`	Java
`Encode`	Java + Perl
`Encode::Alias`	Perl	Dynamic aliases resolved by the Java-backed `Encode` implementation
`Encode::Locale`	Perl	Reuses bundled `ExtUtils::MakeMaker::Locale` locale detection
`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
`XML::LibXSLT`	Java + Perl	Core XSLT transformation API backed by JDK JAXP; requires bundled `XML::LibXML`
`HTML::Parser`	Java
`HTML::Content::Extractor`	Java	Uses jsoup for HTML5 parsing; install the CPAN `.pm` with `jcpan`

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::UTC::Now`	Java + Perl	`java.time.Instant`; reports no trusted accuracy bound
`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
`Object::Pad`	Perl/compiler	Core `class`, `field`, `method`, `:param`, and `:isa` syntax uses PerlOnJava's native class compiler; Object::Pad MOP extensions are not included
`Scalar::Util`	Java
`Sub::Name`	Java
`Sub::Util`	Java
`Class::Struct`	Perl
`Attribute::Handlers`	Perl
`Devel::Cycle`	Perl
`Devel::Peek`	Perl
`Devel::Caller`	Perl + Java	Caller CV and argument introspection used by lexical compatibility modules
`Devel::LexAlias`	Perl + Java	Lexical-cell aliasing for local pads and closures
`PadWalker`	Perl + Java	`peek_sub`, `closed_over`, `set_closed_over`; no `peek_my`, `peek_our`, or `var_name` yet
`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. PerlOnJava ithreads are available, but Moose's thread-specific suite remains only partially classified. See note below.
`B`	Perl	`svref_2object`, `B::CV`/`GV`/`STASH`, `CVf_ANON`, etc. — enough for `Class::MOP::get_code_info` and `B::Deparse`.
`B::Flags`	Perl	Portable `flagspv`/`privatepv` names for the subset of OP/SV state exposed by `B`.

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` and `FILTER_ONLY` closure filters; method filters and true incremental streaming remain unsupported
`Filter::Util::Call`	Java	Closure-based `filter_add`/`filter_read`/`filter_del`; buffered line-oriented emulation, without object/method filters
`Tie::Hash` / `Tie::Array` / `Tie::Scalar`	Perl
`Tie::RefHash`	Perl
`Tie::Hash::Indexed`	Java XS bridge	Ordered tied-hash and object APIs, iterators, arithmetic helpers, and Storable hooks; no native C compiler required

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.

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Bundled Modules Reference

Modules with External Requirements

DBI — Database Access

Image::Magick — Image Processing

Plack::Handler::Netty — Web Server

Moose / Class::MOP

Status

Known limitations

Performance

Module Categories

Core / Pragmas

Data Processing

File & I/O

Network & Web

Database

Cryptography & Encoding

Archives & Compression

XML & HTML

Image Processing

Date & Time

Math

Process Control

Terminal

OOP & Introspection

Testing

Build & Install

Documentation

Java Integration

Miscellaneous

Implementation Types

Adding a New Bundled Module

See Also

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Bundled Modules Reference

Modules with External Requirements

DBI — Database Access

Image::Magick — Image Processing

Plack::Handler::Netty — Web Server

Moose / Class::MOP

Status

Known limitations

Performance

Module Categories

Core / Pragmas

Data Processing

File & I/O

Network & Web

Database

Cryptography & Encoding

Archives & Compression

XML & HTML

Image Processing

Date & Time

Math

Process Control

Terminal

OOP & Introspection

Testing

Build & Install

Documentation

Java Integration

Miscellaneous

Implementation Types

Adding a New Bundled Module

See Also