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Supported Formats
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Common Formats
ZIP Archive - universal compression format developed by Phil Katz (1989) supporting multiple compression methods. Built into Windows, macOS, and Linux. Uses DEFLATE algorithm providing good compression (40-60% reduction) with fast processing. Supports file encryption, split archives, and compression levels. Maximum compatibility across all platforms and devices. Perfect for file sharing, email attachments, web downloads, and general-purpose compression. Industry standard with virtually universal software support including built-in OS tools, mobile apps, and command-line utilities.
RAR Archive - proprietary format by Eugene Roshal (1993) offering superior compression ratios (10-20% better than ZIP) through advanced algorithms. Popular on Windows with WinRAR software. Supports recovery records for damaged archive repair, solid compression for better ratios, strong AES encryption, and split archives up to 8 exabytes. Excellent for long-term storage, large file collections, and backup scenarios. Common in software distribution and file sharing communities. Requires WinRAR or compatible software (not built into most systems).
7-Zip Archive - open-source format by Igor Pavlov (1999) providing the best compression ratio available (20-40% better than ZIP, 10-15% better than RAR). Uses LZMA and LZMA2 algorithms with strong AES-256 encryption. Supports huge file sizes (16 exabytes), multiple compression methods, solid compression, and self-extracting archives. Free from licensing restrictions and patent concerns. Perfect for maximizing storage efficiency, software distribution, and backup archives where size matters. Requires 7-Zip or compatible software but offers exceptional space savings.
Unix Formats
TAR Archive - Tape Archive format from Unix (1979) bundling multiple files and directories into single file without compression. Preserves file permissions, ownership, timestamps, and symbolic links critical for Unix systems. Often combined with compression (TAR.GZ, TAR.BZ2, TAR.XZ) for efficient distribution. Standard format for Linux software packages, system backups, and cross-platform file transfer. Essential for maintaining Unix file attributes. Works with streaming operations enabling network transfers and piping. Foundation of Unix/Linux backup and distribution systems.
GZIP/TGZ - GNU zip compression format (1992) using DEFLATE algorithm, standard compression for Linux and Unix systems. TGZ is TAR archive compressed with GZIP. Fast compression and decompression with moderate ratios (50-70% reduction for text). Single-file compression commonly paired with TAR for multi-file archives. Universal on Unix/Linux systems with built-in 'gzip' command. Perfect for log files, text data, Linux software distribution, and web server compression. Streaming-friendly enabling on-the-fly compression. Industry standard for Unix file compression since the 1990s.
BZIP2/TBZ2 - block-sorting compression format by Julian Seward (1996) offering better compression than GZIP (10-15% smaller) at the cost of slower processing. TBZ2 is TAR archive compressed with BZIP2. Uses Burrows-Wheeler transform achieving excellent ratios on text and source code. Popular for software distribution where size matters more than speed. Common in Linux package repositories and source code archives. Ideal for archival storage, software releases, and situations prioritizing compression over speed. Standard tool on most Unix/Linux systems.
XZ/TXZ - modern compression format (2009) using LZMA2 algorithm providing excellent compression ratios approaching 7Z quality. TXZ is TAR archive compressed with XZ. Superior to GZIP and BZIP2 with ratios similar to 7Z but as single-file stream. Becoming the new standard for Linux distributions and software packages. Supports multi-threading for faster processing. Perfect for large archives, software distribution, and modern Linux systems. Smaller download sizes for software packages while maintaining fast decompression. Default compression for many current Linux distributions.
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{format_tar_bz_desc}
{format_tar_lz_desc}
{format_tar_lzma_desc}
{format_tar_lzo_desc}
{format_tar_z_desc}
TGZ - TAR archive compressed with GZIP compression. Combines TAR's file bundling with GZIP's compression in single extension (.tgz instead of .tar.gz). Standard format for Linux software distribution and source code packages. Maintains Unix file permissions and attributes while reducing size 50-70%. Fast compression and decompression speeds. Universal compatibility on Unix/Linux systems. Perfect for software releases, backup archives, and cross-platform file transfer. Abbreviated form of TAR.GZ with identical functionality and structure.
TBZ2 - TAR archive compressed with BZIP2 compression. Better compression than TGZ (10-15% smaller) but slower processing. Uses Burrows-Wheeler block sorting for excellent text compression. Common in Linux distributions and software packages where size is critical. Maintains Unix file permissions and attributes. Perfect for source code distribution, archival storage, and bandwidth-limited transfers. Abbreviated form of TAR.BZ2 with identical functionality. Standard format for Gentoo Linux packages and large software archives.
TXZ - TAR archive compressed with XZ (LZMA2) compression. Modern format offering best compression ratios for TAR archives (better than TGZ and TBZ2). Fast decompression despite high compression. Supports multi-threading for improved performance. Becoming standard for Linux distributions (Arch, Slackware use TXZ). Maintains Unix permissions and symbolic links. Perfect for large software packages, system backups, and efficient storage. Abbreviated form of TAR.XZ representing the future of Unix archive compression.
LZMA/TAR.LZMA - Lempel-Ziv-Markov chain Algorithm compression format (2001) offering excellent compression ratios. TAR.LZMA combines TAR archiving with LZMA compression. Predecessor to XZ format using similar algorithm but older container format. Better compression than GZIP and BZIP2 but superseded by XZ/LZMA2. Still encountered in older Linux distributions and legacy archives. Slower compression than GZIP but better ratios (similar to XZ). Modern systems prefer TAR.XZ over TAR.LZMA. Legacy format for accessing older compressed archives from 2000s era.
LZO/TAR.LZO - Lempel-Ziv-Oberhumer compression format prioritizing speed over compression ratio. TAR.LZO is TAR archive compressed with LZO. Extremely fast compression and decompression (faster than GZIP) with moderate ratios (30-50% reduction). Popular in real-time applications, live systems, and scenarios requiring instant decompression. Used by some Linux kernels and embedded systems. Common in backup solutions prioritizing speed. Perfect for temporary compression, live CD/USB systems, and high-speed data transfer. Trade-off: larger files than GZIP/BZIP2/XZ but much faster processing.
Z/TAR.Z - Unix compress format from 1985 using LZW (Lempel-Ziv-Welch) algorithm. TAR.Z is TAR archive compressed with compress command. Historical Unix compression format predating GZIP. Patent issues (until 2003) led to GZIP replacing it. Legacy format with poor compression by modern standards. Rarely used today except in very old Unix systems and historical archives. If you encounter .Z or .tar.Z files, convert to modern formats (TAR.GZ, TAR.XZ) for better compression and wider support. Important for accessing ancient Unix archives from 1980s-1990s.
Specialized Formats
ISO Image - ISO 9660 disk image format containing exact sector-by-sector copy of optical media (CD/DVD/Blu-ray). Standard format for distributing operating systems, software installations, and bootable media. Can be mounted as virtual drive without physical disc. Contains complete filesystem including boot sectors, metadata, and file structures. Essential for Linux distributions, system recovery media, and software archives. Used by burning software, virtual machines, and media servers. Universal standard with support in all major operating systems for mounting and burning.
Cabinet Archive - Microsoft's compression format for Windows installers and system files. Used extensively in Windows setup packages, driver installations, and system updates. Supports multiple compression algorithms (DEFLATE, LZX, Quantum), split archives, and digital signatures. Built into Windows with native extraction support. Common in software distribution for Windows applications, particularly older installers and Microsoft products. Maintains Windows-specific attributes and can store multiple files with folder structures. Part of Windows since 1996.
AR Archive - Unix archiver format (1970s) originally for creating library archives (.a files). Simple format storing multiple files with basic metadata (filename, modification time, permissions). Used primarily for static libraries in Unix development (.a extension). Foundation format for DEB packages (Debian packages are AR archives containing control and data). Minimal compression support (none by default). Essential for Unix library management and Debian package structure. Standard tool 'ar' included on all Unix/Linux systems. Simple and reliable for static file collections.
Debian Package - software package format for Debian, Ubuntu, and derivative Linux distributions. Contains compiled software, installation scripts, configuration files, and dependency metadata. Used by APT package manager (apt, apt-get commands). Actually a special AR archive containing control files and data archives. Essential format for Debian-based Linux software distribution. Includes pre/post-installation scripts, version management, and dependency resolution. Standard packaging for thousands of Ubuntu/Debian applications. Can be inspected and extracted as regular archive.
RPM Package - Red Hat Package Manager format for Red Hat, Fedora, CentOS, SUSE, and derivative Linux distributions. Contains compiled software, installation metadata, scripts, and dependency information. Used by YUM and DNF package managers. Includes GPG signature support for security verification. Standard for Red Hat Enterprise Linux ecosystem. Supports pre/post-installation scriptlets, file verification, and rollback capabilities. Essential format for RHEL-based Linux software distribution. Can be extracted as archive to inspect contents without installation.
JAR Archive - Java Archive format based on ZIP compression for packaging Java applications. Contains compiled Java classes (.class files), application resources, and manifest metadata. Standard distribution format for Java applications and libraries. Supports digital signatures for code verification. Can be executable (runnable JAR files with Main-Class manifest). Perfect for Java application deployment, library distribution, and plugin systems. Compatible with ZIP tools but includes Java-specific features. Essential format for Java development and deployment since 1996.
ARJ Archive - legacy DOS compression format by Robert Jung (1991). Popular in DOS and early Windows era for its good compression ratio and ability to create multi-volume archives. Supports encryption, damage protection, and archive comments. Largely obsolete today, replaced by ZIP, RAR, and 7Z. Still encountered in legacy systems and old software archives. Requires ARJ or compatible decompression software. Historical format important for accessing old DOS/Windows archives from 1990s. Better converted to modern formats for long-term accessibility.
LHA Archive - Japanese compression format (also LZH) developed in 1988, extremely popular in Japan and with Amiga users. Uses LZSS and LZHUF compression algorithms providing good ratios. Common for Japanese software distribution in 1990s. Supports archive headers, directory structures, and file attributes. Legacy format now mostly replaced by modern alternatives. Still encountered in retro computing, Japanese software archives, and Amiga communities. Requires LHA/LZH compatible software for extraction. Important for accessing Japanese and Amiga software archives.
CPIO Archive - Copy In/Out archive format from Unix (1970s) for creating file archives. Simpler than TAR, often used for system backups and initramfs/initrd creation. Standard format for Linux initial RAM disk images. Supports multiple formats (binary, ASCII, CRC). Better handling of special files and device nodes than TAR. Common in system administration, bootloader configurations, and kernel initrd images. Universal on Unix/Linux systems. Essential for system-level archiving and embedded Linux systems. Works well for streaming operations.
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Frequently Asked Questions
What is a JAR file and why is it used in Java applications?
A JAR file (Java ARchive) is a package format that bundles Java classes, resources, images, libraries, and metadata into a single ZIP-based container. It allows developers to ship entire Java programs or components as one portable file instead of distributing dozens or hundreds of individual .class files and resource folders.
Because JARs follow the ZIP standard, they compress contents efficiently while preserving directory structure and metadata essential for Java’s class-loading system. This makes JARs ideal for deployment, modularization, and sharing reusable code libraries.
Many Java applications, web servers, Android build tools, game engines, and enterprise systems depend on JAR packaging for predictable loading, easy distribution, and consistent runtime behavior across platforms.
Why can some JAR files run directly while others cannot?
Only executable JARs include a manifest entry specifying which class contains the application's main() method. This entry, Main-Class, instructs the Java Runtime which file to execute.
Library JARs are not meant to be launched. They contain classes and resources intended to be imported by other applications rather than run standalone.
Tooling also matters: some JARs require additional classpath dependencies. If those are missing, the JAR cannot run on its own even if it has an entry point.
Why are JAR files sometimes larger than expected?
JARs commonly include multiple libraries, configuration files, icons, translations, and other assets bundled together for simplicity.
Some JARs contain compiled bytecode for multiple platforms or embed third-party frameworks, causing size increases.
Minification and shading are optional steps; many developers choose convenience over optimization, resulting in larger files.
Why do JAR files throw 'ClassNotFoundException' even when the class exists?
JARs depend on precise package paths. If the internal directory structure does not match the package declaration, Java cannot locate the class.
Classpath misconfiguration—especially when mixing multiple JARs—often prevents the runtime from finding required dependencies.
Shaded or repackaged libraries may also shift class locations, breaking references unless relocation is configured correctly.
Why does extracting a JAR not show the same folder structure as the source project?
Source code directories are transformed into compiled bytecode outputs, removing development paths that existed only during compilation.
Build tools like Maven and Gradle often reorganize resources, merging them from multiple modules into the final artifact.
JARs intentionally omit source folders to reduce size unless a separate *-sources.jar is created.
How secure are JAR files?
Unsigned JARs can be modified without detection, making them vulnerable in untrusted environments.
Signed JARs use cryptographic certificates to verify authenticity, ensuring the archive has not been altered.
However, even signed JARs may contain unsafe code; signing only ensures identity, not safety. Sandboxing and JVM security policies are still needed.
Why do JAR files sometimes require a specific Java version?
Java bytecode evolves. If a JAR is compiled using features from a newer Java version, older JVMs cannot recognize the class file format.
Modules and new APIs introduced in later Java versions may also be missing on older runtimes.
Build tools commonly set a target Java version; mismatched environment settings lead to incompatible JARs.
Why does a JAR fail with 'Invalid or corrupt jarfile'?
Truncated downloads or corrupted transfers can break the ZIP structure inside a JAR.
Non-ZIP data at the start of the file—such as from merging or wrapping—causes the JVM to reject it.
Improper packaging, such as compressing a JAR inside another JAR without correct structure, can also render it unreadable.
Why do developers package dependencies directly inside JARs?
Fat JARs or Uber JARs simplify deployment by bundling every dependency inside one file, eliminating classpath configuration issues.
Shading avoids version conflicts by relocating dependency packages under unique namespaces.
This approach is especially useful for CLI applications, serverless deployments, and standalone utilities.
Why are modular JARs different from regular ones?
Java 9 introduced JPMS modules, allowing JARs to define explicit exports, dependencies, and access rules.
Module descriptors expose a cleaner dependency graph and reduce classpath ambiguity.
Modular JARs improve performance and security but require careful configuration to avoid module-resolution failures.
Why does my JAR work in my IDE but not when executed manually?
IDEs automatically set up classpaths, resource paths, and dependency resolution behind the scenes.
When running manually, missing dependencies, incorrect directories, or missing manifests cause failures.
Environment differences—Java version, working directory, OS path formats—also affect runtime behavior.
Why does updating a JAR not update an application immediately?
Cached classloaders—especially in servers—may keep old versions in memory until a full restart occurs.
Some systems require clearing plugin folders or dependency caches to load updated artifacts.
Packaging tools may reuse old build outputs if caches aren’t cleaned before compiling.
Why does JAR performance differ across environments?
Different JVM implementations optimize bytecode execution differently, affecting runtime speed.
Hardware differences—CPU architecture, garbage collector behavior, available memory—impact execution efficiency.
Background services, disk speed, and operating system scheduling also influence performance.
Why is JAR still widely used despite newer alternatives like JMOD or WAR?
JAR is universally supported across all JVMs and requires no special tooling to execute or extract.
It is extremely flexible: suitable for apps, libraries, plugins, and build artifacts without format changes.
Most Java ecosystems, build tools, and frameworks are built around JARs, ensuring long-term relevance.
Should you choose JAR as your main packaging format?
Choose JAR if you need a portable, cross-platform container for Java libraries or applications.
It is ideal for reusable libraries, CLI tools, microservices, plugin systems, and modular components.
For applications with many dependencies or deployment complexity, consider fat JARs, WAR/EAR packages, or containerized solutions.