v4.3.1

4.3.1 (2026-06-29)

Bug Fixes

• detect BOM correctly on short streams in BomInputStream (efc1633)
• prevent ArrayIndexOutOfBoundsException in NamedCsvRecord.findFields (0a05a0b)
• prevent data corruption after seek in IndexedCsvReader with multibyte charsets (c7d45ff)
• prevent skipLine from resurrecting an unterminated last line at EOF (be02dab)
• reject non-ASCII-compatible charsets in IndexedCsvReader (8cc6ea8)

v4.3.0

4.3.0 (2026-05-09)

Features

• add allowUnclosedQuote flag to reader builders (#173) (171101a)
• lock skipLines once CSV parsing has started (fb018d2)

Bug Fixes

• clear stale CR flag on closing quote in StrictCsvParser (a6d3de5)
• peekLine in RelaxedCsvParser truncated long lines (ce86205)
• peekLine left buffer in inconsistent state after compaction (0819c4f)
• reset() in StrictCsvParser left parser-state fields stale (9c0d607)

v4.2.0

4.2.0 (2026-04-04)

Features

• add FieldMismatchStrategy to replace allowExtraFields/allowMissingFields (b1049ac), closes #176

v4.1.1

4.1.1 (2026-03-08)

Bug Fixes

• correct BomInputStream buffer offset for short inputs (#174) (1275474)

Performance Improvements

• precompute comment strategy check in parser (6d6e874)
• use range check in fast-forward loops (85eb73f)

Release v4.1.0

Release v4.1.0

🚀 Features

• 960d8c8 ignore same comment character if comments are ignored

🧰 Tasks

• f707599 update changelog
• 55633f5 version bump
• f0f04f3 version bump

🛠 Build

• 8a6759f disable configuration cache for jReleaser
• 4b582d0 deps: update jReleaser dependency
• b55eb75 updated gradle tasks
• ee41d8a OSS-Fuzz requires JDK 17
• 05c99fb add foojay-resolver to buildSrc
• 9e029e6 website: update dependencies
• ad76e78 update to JUnit 6
• eb5af63 use Java 25 to build
• 0c142d9 codeql does currently not support arm-based runners
• 1d141c0 website: update dependencies
• e844d06 update setup-java action
• 5b79b63 try arm-based runner
• 313e584 try arm-based runner
• 3dc1d4d update checkout action
• c4b0aa8 website: update dependencies
• b35ffc3 updated Gradle, enabled configuration cache

📝 Documentation

• 48f7c1e use Java 25 syntax for examples
• 40b7cd6 website: add example for interpreting empty fields as null values
• 0392eb8 website: add JUnit and order prominent users alphabetically
• 50b78b4 website: update benchmarks
• 619aec5 website: update website dependencies
• 60baf89 website: refer to 4.0.0

Release v4.0.0

See the upgrade guide on how to switch from version 3.x smoothly.

🚀 Features

• 18688cc add returnHeader to NamedCsvRecordHandler to allow early-access to the header #147, closes #147
• e006347 add ofSingleCsvRecord methods to CsvReader for convenience
• 60774d3 🚨 enforce unique headers by default
• bd9991f introduce relaxed parsing mode for CsvReader

🐛 Fixes

• 76dff29 don't call peek line predicate with empty string if reached EOF

🔄️ Changes

• a565316 add missing finals
• 57da808 optimize performance of relaxed parser
• 77b986c change skipLine method to void and handle EOF exceptions
• c815d3e simplify BOM handling in CsvReader #149, closes #149
• 52fe46d add class retention to allow incremental builds
• cef4a2b later buffer expansion
• 47cca27 refactor EOF handling when peeking lines
• bba1412 introduce Nullable annotation
• 98aeaab 🚨 return Optional for throwable in status listener
• 1130197 use errorprone
• ef14cb7 change exception type from IllegalArgumentException to IllegalStateException for relaxed mode validation
• b1b5f23 simplify quoted parsing logic in RelaxedCsvParser
• 08194a4 remove dead code
• ced8dd3 introduce LookaheadReader to improve the performance of RelaxedCsvParser
• 1bc5f26 🚨 convert FieldModifiers class to enum and move modify method to FieldModifier interface
• d1e5943 remove unnecessary 'this' keyword in variable assignments
• cb5a999 🚨 rename quoteNonEmpty method to quoteValue and made quoteStrategy non-nullable
• 5fbfe91 update method name for allowing duplicate header fields in NamedCsvRecordHandler
• 5980793 simplify materializeField logic and adjust return flow
• 056c865 🚨 CSV callback handling and record type logic
• 85bbfdf 🚨 Refactor field count handling in CsvReader
• 4107892 simplify validation error messages and add a new test
• dd00979 extract csv parser interface to allow multiple implementations
• 3ac07d1 🚨 strict handling of characters after closing quote, by default
• 9d8511b seal AbstractInternalCsvCallbackHandler for internal use (as documented before)
• a33384e use unnamed variables (_) in lambdas to simplify tests
• 2babea6 🚨 disable automatic buffer flushing for writer use
• 403c2f6 use skipNBytes for skipping a detected BOM
• 0d05add 🚨 removed deprecated code (Limits and SimpleFieldModifier)
• 9e620a3 corrected method name in error message
• 006380c 🚨 remove the RecordWrapper
• 430adef add Serial annotation
• 724bc38 🚨 changed implementation of CsvIndex and CsvPage to Java records
• 3e11bfc use formatted Strings
• 01f5cb3 use switch expression

🧪 Tests

• 6e43efb add benchmark for relaxed parser
• 150b68e add missing tests

🧰 Tasks

• 3e3edcb update dependencies for test and build; refactor internal code to keep SpotBugs happy
• 0a0136c prepare (clean) upgrading.md for a new major release
• ba1a894 bump version to 4.0.0-SNAPSHOT

🛠 Build

• f990d39 update resolver plugin
• 03f4a49 bump version to 4.0.0
• f14dab0 updated Gradle
• 0d97d92 updated build/test dependencies
• 2cd4ac1 add SPDX-License-Identifier to MANIFEST.MF
• a3aafac update pitest version for Java 24 compatibility
• 541b39e include LICENSE file in META-INF directory for use in dependent libraries
• d14aef6 enable parameter names for tests with @ParameterizedTest
• 7584ab9 update PMD and remove unnecessary suppressions
• d8fadf0 🚨 require Java 17 / Android 34
• 280ab79 let JReleaser manage the CHANGELOG.md

📝 Documentation

• c248a38 document array wrapping usage
• f10e7ea update copyright year in LICENSE file
• e5fff5a align with Java 17

v3.7.0

Added

• FieldModifiers.modify(Function<String, String>) to simply modify fields via functional interface

Deprecated

• SimpleFieldModifier interface
• FieldModifiers.lower and FieldModifiers.upper methods

v3.6.0

Added

• Configuration of maximum fields, maximum field size, and maximum record size via record handler
• Fluent configuration for CsvRecordHandler, NamedCsvRecordHandler, and StringArrayHandler
• maxBufferSize(int) in CsvReaderBuilder and IndexedCsvReaderBuilder to alter the maximum buffer size of the parser

Changed

• Use ReentrantLock in IndexedCsvReader instead of synchronized to prevent pinning of virtual threads
• More precise error messages when exceeding the maximum field or record size
• More precise error when parsing error occurs within IndexedCsvReader
• Apply length constraints (maximum field size and maximum record size) after applying field modifiers

Deprecated

• Setting the maximum field size (and maximum buffer size) via system property fastcsv.max.field.size
• Setting the maximum field count per record via system property fastcsv.max.field.count
• Constructor initialization of CsvRecordHandler, NamedCsvRecordHandler, and StringArrayHandler

v3.5.0

Added

• Support InputStream as an input source for CsvReader including BOM detection #130
• Support OutputStream as an output target for CsvWriter

v3.4.0

Added

• Add skipLines(int) and skipLines(Predicate<String>, int) to CsvReader to skip lines before the actual CSV data starts