JAR to CPIO Converter

Transform JAR archives into CPIO format — free online

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JAR to CPIO Faithfully

The complete file tree from your JAR archive is reproduced in the CPIO output. Directories, nested structures, and every individual file transfer without modification.

Works on Any Device

No software to install — access the converter from a desktop, laptop, phone, or tablet. Any modern browser on any operating system is all you need.

Automatic File Purge

Uploaded JAR archives disappear from our servers right after conversion. CPIO output files are automatically removed within 24 hours to ensure data privacy.

How to convert JAR to CPIO

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

Choose cpio or any other format you need as a result (more than 200 formats supported)

Let the file convert and you can download your cpio file right afterwards

About formats

JAR (Java Archive) is a package file format based on ZIP, developed by Sun Microsystems and introduced with JDK 1.1 in January 1996 for distributing Java class files, associated metadata, and resources as a single deployable unit. A JAR file is structurally a ZIP archive with an added META-INF/MANIFEST.MF file — a text manifest that declares the archive's main class entry point, classpath dependencies, package versioning, and digital signature information. The Java runtime loads classes directly from JAR files without extraction, using the ZIP directory for efficient random access to individual entries. JAR archives can be made executable: specifying a Main-Class attribute in the manifest allows launching the application with a simple java -jar command. The format supports code signing through the JDK's jarsigner tool, embedding digital signatures that verify the authenticity and integrity of the archive's contents. One advantage is the Java ecosystem's native integration — the JVM, build tools (Maven, Gradle), application servers, and IDEs all treat JAR files as first-class artifacts, enabling a unified build-deploy-run pipeline. The format's backward compatibility with standard ZIP tools is another practical strength: any ZIP utility can inspect JAR contents, while the manifest and signing layers add Java-specific capabilities on top. JAR remains the fundamental distribution unit for Java libraries and applications across enterprise, mobile, and embedded deployments.

Developer: Sun Microsystems

Initial release: January 23, 1996

CPIO (Copy In, Copy Out) is a Unix archive format dating to the PWB/UNIX system at AT&T Bell Labs in 1977, predating even the tar format. The name describes the tool's original operation: copying files in to an archive and out from an archive. CPIO stores files sequentially with per-file headers containing the filename, inode information, permissions, ownership, timestamps, and file size, followed by the file data itself. The format exists in several variants: the original binary format, the POSIX.1-defined octet-oriented (ODC) format, the SVR4 newc format with expanded device and inode fields, and the CRC variant that adds checksum verification. Unlike tar, CPIO reads the list of files to archive from standard input, making it naturally composable with find and other Unix utilities through pipes. One advantage is faithful Unix metadata preservation — CPIO records device numbers, inode information, and hard link relationships with higher fidelity than early tar implementations, making it suitable for system-level backups and device file archiving. The format's central role in Linux package management is another practical significance: the RPM package format uses CPIO as its internal payload container, meaning every RPM-based Linux installation relies on CPIO extraction. While tar has become more common for general archiving, CPIO persists in system administration, initramfs images, and package management infrastructure.

Developer: AT&T / Unix

Initial release: 1977

Frequently Asked Questions

Why convert JAR to CPIO?

CPIO is required for RPM package creation, Linux initramfs images, and certain system-level scripts. Converting a JAR to CPIO provides the specific container format these tools demand.

How do I extract a CPIO file?

The cpio command is standard on all Unix/Linux systems. On Windows, 7-Zip opens CPIO archives. macOS Terminal also includes cpio for extraction.

Are all files from the JAR included?

Yes. Every file — Java classes, manifests, resources, and subdirectories — transfers from the JAR into the CPIO archive with paths and names intact.

Can I convert multiple JARs to CPIO?

You can. Upload a batch of JAR files on convertio.tools and convert them all to CPIO at once — efficient and time-saving.

Is there a charge for this?

Not for basic use. JAR to CPIO conversion is free on convertio.tools. Premium users get enhanced limits and faster processing.

Does it work on a Chromebook?

Perfectly. The converter is entirely browser-based — Chromebooks, tablets, and any device with a web browser can use it without restrictions.

Related Conversions

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JAR to TGZ

JAR to CPIO

JAR to TAR.BZ

JAR to TAR.XZ

JAR to TAR

JAR to TBZ2

JAR to LHA

JAR to TAR.LZMA

JAR to TAR.7Z

JAR to TAR.Z

JAR to TAR.LZ

JAR to TAR.LZO

Specific converters

ZIP to CPIO

RAR to CPIO

JAR to CPIO

7Z to CPIO

TAR to CPIO

RPM to CPIO

TGZ to CPIO

LHA to CPIO

CAB to CPIO

ACE to CPIO

ALZ to CPIO

ARC to CPIO

ARJ to CPIO

DEB to CPIO

TAR.7Z to CPIO

TAR.BZ to CPIO

TAR.LZ to CPIO

TAR.LZMA to CPIO

TAR.LZO to CPIO

TAR.XZ to CPIO

TAR.Z to CPIO

TBZ2 to CPIO

JAR to CPIO Quality Rating

4.7 (12 votes)

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