Gson 2.11.0

Most important changes

• Added default ProGuard / R8 rules (@Marcono1234, #2397, #2420; @sgjesse, #2448; @sfreilich)
  If you are using ProGuard or R8 (for example for Android projects) you might not need any special Gson configuration anymore if your classes have a no-args constructor and use @SerializedName for their fields.
• On Android, Gson now requires API level 21 or newer
• Added new Strictness API (@marten-voorberg & fellow students, #2437)
  Some of Gson's API is still lenient by default, but you can now use the newly added methods GsonBuilder#setStrictness, JsonReader#setStrictness and JsonWriter#setStrictness with Strictness.STRICT to override this behavior and to instead strictly adhere to the JSON specification when parsing.
• New FormattingStyle class to allow configuring line breaks in JSON output (@mihnita, #2231)
  Can be set using GsonBuilder#setFormattingStyle and JsonWriter#setFormattingStyle.
• TypeToken can no longer capture type variables by default (@Marcono1234, #2376)
  This was previously a common source of issues. The newly thrown exception refers to a Troubleshooting Guide article which explains this in more detail and provides suggestions for updating affected code.
• Added serialization support for anonymous and local classes with a custom adapter (@Marcono1234, #2498)
  This affects for example List implementations returned by libraries such as Guava which are implemented as anonymous class, which were previously serialized as null. Anonymous and local classes without custom adapter will still be serialized as null.
• Added dependency on com.google.errorprone:error_prone_annotations
  Your project can use Maven or Gradle dependency exclusions to remove the transitive error_prone_annotations dependency from Gson. Or if you are manually maintaining dependencies as JARs in your project you can omit error_prone_annotations. And it should still work correctly.
  But Gson itself does declare it as a required dependency, and if you don't perform any custom configuration, then Maven or Gradle will by default try to download and use it.
• Many exception messages now refer to the Troubleshooting Guide (@Marcono1234, #2357)
  Feedback regarding the Troubleshooting Guide is appreciated!
• Officially documented that JVM languages other than Java might not be fully supported, see the README.
• Guarantee that JsonElement#toString produces JSON output (@Marcono1234, #2659)

Other changes

Bug fixes

• Fixed incorrect JsonPrimitive#equals results for large BigInteger values (@MaicolAntali, #2311)
• Fixed incorrect JsonPrimitive#equals results for large BigDecimal values (@MaicolAntali, #2364)
• Fixed JsonReader throwing NumberFormatException instead of MalformedJsonException for malformed Unicode escape sequences (@MaicolAntali, #2337)
• Fixed TypeToken#getParameterized returning bogus ParameterizedType for non-generic types (@Marcono1234, #2447)
• Fixed Java Record adapter not working for GraalVM Native Image (@eamonnmcmanus, #2465)
• Fixed JsonWriter#name not throwing exception when no JSON object is currently being written (@shivam-sehgal, #2475; @Marcono1234, #2476)
• Fixed Gson#getDelegateAdapter not working properly for @JsonAdapter (@Marcono1234, #2435)
  Note that null is now not allowed as skipPast value anymore, which was previously allowed but undocumented.
• Fixed GsonBuilder not rejecting type adapters for Object and JsonElement, whose default adapters cannot be overridden (@sachinp97; #2479)
• Fixed no limits being enforced when deserializing BigDecimal and BigInteger (@Marcono1234, #2510)
  The new limits prevent potential performance problems when user code uses the deserialized numbers. Gson itself was and is not affected by these performance problems. The limits should be high enough to not cause issues for most use cases, but feedback is appreciated.
• Fixed GsonBuilder#setDateFormat not rejecting invalid date formats (@Carpe-Wang, #2538)
• Fixed GsonBuilder#setDateFormat not rejecting invalid date styles (@Marcono1234, #2545)
• Fixed GsonBuilder#setDateFormat ignoring partial DEFAULT style (@Marcono1234, #2556)
• Fixed TypeToken#isAssignableFrom throwing AssertionError in some cases (@Marcono1234, #2544)
• Fixed date adapters not restoring time zone after parsing (@Carpe-Wang, #2549)
• Fixed TypeToken#equals erroneously returning false for equal generic type parameters in some cases (@d-william, #2599)
• Fixed incorrect inherited URLs in pom.xml (@Marcono1234, #2351)

Performance improvements

• Slightly reduce memory usage for reflection-based adapter (@sembseth, #2325; @Marcono1234, #2440)
• Improved parsing speed of ToNumberPolicy#LONG_OR_DOUBLE (@ctasada, #2674)

Gson maintenance

• Changed many unit tests to use Truth instead of JUnit for assertions (@MaicolAntali, #2299, #2304)
• Configured Error Prone to automatically check for bugs when compiling (@MaicolAntali, #2308)
• Simplified expected exception handling in tests (@elevne, #2454)
• Added integration test for GraalVM Native Image (@Marcono1234, #2466)
• Formatted the code according to the Google Style Guide & configured Spotless (@MaicolAntali, #2531, #2537)
• Made Maven build reproducible (@Marcono1234, #2543)
• Removed internal DateTypeAdapter class to reduce code duplication (@Marcono1234, #2546)
• Dependencies and plugins updated by Dependabot

GitHub repository

• Renamed default branch from master to main
• GitHub Discussions have been enabled
  For questions, ideas, tips...
• Added GitHub pull request template (@Marcono1234, #2326)
• Added check for Android API compatibility (@Marcono1234, #2431)

Other

• Added @CanIgnoreReturnValue as appropriate to Gson methods (@eamonnmcmanus, #2369)
  This is useful if you enable Error Prone's CheckReturnValue in your project when compiling, however Gson itself does not enable this by default.
• Various documentation and test improvements and typo fixes (@False-Mask; @avimathur009; @elevne; @0o001; @Codegass; @33nya)

---

Many thanks to @Marcono1234 for drafting these release notes.

Gson 2.10.1

This is technically a minor release rather than a patch release because there is one small API change: a new JsonObject.isEmpty() method.

What's Changed: User-Visible Changes

• Added JsonObject method isEmpty() by @dhoard in #2233
• Fix non-threadsafe creation of adapter for type with cyclic dependency by @Marcono1234 in #1832
• Remove EOFException special casing of JsonStreamParser.next() by @Marcono1234 in #2281
• Improve exception message for duplicate field names by @Marcono1234 in #2251
• Fix the javadoc of JsonDeserializer.deserialize() by @MaicolAntali in #2243
• Bump os-maven-plugin from 1.7.0 to 1.7.1 by @dependabot in #2235
• Bump jackson-databind from 2.13.4.2 to 2.14.0 by @dependabot in #2234
• Bump maven-release-plugin from 3.0.0-M6 to 3.0.0-M7 by @dependabot in #2232
• Bump japicmp-maven-plugin from 0.16.0 to 0.17.1 by @dependabot in #2238
• Bump jackson-databind from 2.14.0 to 2.14.1 by @dependabot in #2241
• Bump bnd-maven-plugin from 6.3.1 to 6.4.0 by @dependabot in #2245

Site Documentation and Maintenance Changes (these were already visible)

• Add troubleshooting guide by @Marcono1234 in #2285
• Replace custom user guide header anchors by @Marcono1234 in #2289
• Improve variable names in user guide by @Marcono1234 in #2290
• Add 2.10 changes to CHANGELOG; minor release follow-ups by @Marcono1234 in #2229
• Mention in CHANGELOG that GitHub Releases are used in the future by @Marcono1234 in #2230
• GitHub Workflows security hardening by @sashashura in #2274

Other Changes

• Making consistent prefixs in PerformanceTest by @CirQ in #1760
• Adjust version numbers and a test to conform to the SemVer spec. by @eamonnmcmanus in #2237
• Remove covered condition in JsonNull.equals() by @MaicolAntali in #2271
• Remove the final keyword from private method by @MaicolAntali in #2276
• Code cleanup by @MaicolAntali in #2282
• Unnecessary unboxing at JsonPrimitive.getAsBoolean() by @MaicolAntali in #2277
• Rewrite the testParsingDatesFormattedWithSystemLocale(), Fix #2199 by @MaicolAntali in #2287
• Port tests from JUnit 3 to JUnit 4 by @MaicolAntali in #2294

New Contributors (thanks!)

• @CirQ made their first contribution in #1760
• @dhoard made their first contribution in #2233
• @MaicolAntali made their first contribution in #2243
• @sashashura made their first contribution in #2274

Full Changelog: gson-parent-2.10...gson-parent-2.10.1

Gson 2.10

Most important changes

• Support for serializing and deserializing Java records, on Java ≥ 16. (#2201)

• Add JsonArray.asList and JsonObject.asMap view methods (#2225)

• Fix TypeAdapterRuntimeTypeWrapper not detecting reflective TreeTypeAdapter and FutureTypeAdapter (#1787)

• Improve JsonReader.skipValue() (#2062)

• Perform numeric conversion for primitive numeric type adapters (#2158)

• Add Gson.fromJson(..., TypeToken) overloads (#1700)

• Fix changes to GsonBuilder affecting existing Gson instances (#1815)

• Make JsonElement conversion methods more consistent and fix javadoc (#2178)

• Throw UnsupportedOperationException when JsonWriter.jsonValue is not supported (#1651)

• Disallow JsonObject Entry.setValue(null) (#2167)

• Fix TypeAdapter.toJson throwing AssertionError for custom IOException (#2172)

• Convert null to JsonNull for JsonArray.set (#2170)

• Fixed nullSafe usage. (#1555)

• Validate TypeToken.getParameterized arguments (#2166)

• Fix #1702: Gson.toJson creates CharSequence which does not implement toString (#1703)

• Prefer existing adapter for concurrent Gson.getAdapter calls (#2153)

• Improve ArrayTypeAdapter for Object[] (#1716)

• Improve AppendableWriter performance (#1706)

List of all changes

• Improve AppendableWriter performance by @Marcono1234 in #1706
• Improve ArrayTypeAdapter for Object[] by @Marcono1234 in #1716
• Prefer existing adapter for concurrent Gson.getAdapter calls by @Marcono1234 in #2153
• Fix #1702: Gson.toJson creates CharSequence which does not implement toString by @Marcono1234 in #1703
• Deprecate JsonElement constructor by @Marcono1234 in #1761
• Validate TypeToken.getParameterized arguments by @Marcono1234 in #2166
• Fixed nullSafe usage. by @bufistov in #1555
• Convert null to JsonNull for JsonArray.set by @Marcono1234 in #2170
• Clarify that GsonBuilder.setExclusionStrategies does not replace existing ones by @Marcono1234 in #2168
• Fix typo by @JamesZBL in #1246
• Remove not needed .gitattributes file by @Marcono1234 in #1862
• Improve InternationalizationTest by @Marcono1234 in #1705
• Fix JsonWriter documentation regarding top-level value by @Marcono1234 in #1766
• Fix JsonTreeReader throwing wrong exception type for non-finite doubles by @Marcono1234 in #1782
• Clarify doc about non-finite numbers for non-lenient JsonReader by @Marcono1234 in #1723
• Fix TypeAdapter.toJson throwing AssertionError for custom IOException by @Marcono1234 in #2172
• Add test for JsonArray.isEmpty() by @LorenzNickel in #2173
• Disallow JsonObject Entry.setValue(null) by @Marcono1234 in #2167
• Improve GsonTest.testGetAdapter_Concurrency by @Marcono1234 in #2177
• Add null checks for GsonBuilder methods by @Marcono1234 in #2179
• Throw UnsupportedOperationException when JsonWriter.jsonValue is not supported by @Marcono1234 in #1651
• Make JsonElement conversion methods more consistent and fix javadoc by @Marcono1234 in #2178
• Bump maven-javadoc-plugin from 3.4.0 to 3.4.1 by @dependabot in #2175
• Add tests checking GsonBuilder not affecting existing Gson instances by @Marcono1234 in #1815
• Fix #1697: Mention that GsonBuilder.registerTypeAdapter makes (de-)serializers null-safe by @Marcono1234 in #1704
• Replace $Gson$Preconditions.checkNotNull with Objects.requireNonNull by @Marcono1234 in #2180
• Verify that JsonTreeReader and JsonTreeWriter override all methods by @Marcono1234 in #2181
• Fail Maven build on compiler warnings; remove some warning suppressions by @Marcono1234 in #2183
• Add GitHub workflow for checking API compatibility by @Marcono1234 in #2182
• Bump japicmp-maven-plugin from 0.15.7 to 0.16.0 by @dependabot in #2187
• Bump jackson-databind from 2.13.3 to 2.13.4 by @dependabot in #2191
• Remove usage of oss-parent Maven parent and update ReleaseProcess.md by @Marcono1234 in #2159
• Improve documentation by @Marcono1234 in #2193
• updated JsonDeserializer example by @deeptimarrivada1 in #2192
• Add Gson.fromJson(..., TypeToken) overloads by @Marcono1234 in #1700
• Bump maven-jar-plugin from 3.2.2 to 3.3.0 by @dependabot in #2195
• Build on JDK 17 as well as 11. by @eamonnmcmanus in #2198
• Fix incorrect HTML headings in Javadoc by @Marcono1234 in #2200
• Add a currently-failing test for Java records and @Ignore it. by @eamonnmcmanus in #2203
• Follow-up for record test build changes by @Marcono1234 in #2207
• Disable Maven transfer progress for GitHub workflows by @Marcono1234 in #2206
• Only create one UnsafeAllocator instance by @kb-1000 in #2196
• Mention in User Guide alternative for Gson versions without fromJson(..., TypeToken) by @Marcono1234 in #2209
• Fix typo in GsonBuilder Javadoc by @BillyGalbreath in #2213
• Add Javadoc @since tags for previously added elements by @Marcono1234 in #2211
• Improve versioning support documentation and validate version by @Marcono1234 in #2214
• Perform numeric conversion for primitive numeric type adapters by @Marcono1234 in #2158
• Clarify in documentation that Gson might cache strategy results by @Marcono1234 in #2215
• Improve JsonReader.skipValue() by @Marcono1234 in #2062
• Fix TypeAdapterRuntimeTypeWrapper not detecting reflective TreeTypeAdapter and FutureTypeAdapter by @Marcono1234 in #1787
• Support Java Records when present in JVM. by @staale in #2201
• Small adjustments to the new record code. by @eamonnmcmanus in #2219
• Bump jackson-databind from 2.13.4 to 2.13.4.1 by @dependabot in #2222
• Bump jackson-databind from 2.13.4.1 to 2.13.4.2 by @dependabot in #2223
• Add JsonArray.asList and JsonObject.asMap view methods by @Marcono1234 in #2225
• Adjust Record adapter and extend test coverage by @Marcono1234 in #2224
• Small tweaks to fix Error Prone warnings. by @eamonnmcmanus in #2227
• Automatically replace version references on release:prepare by @Marcono1234 in #2212
• Revise the version regex in GsonVersionDiagnosticsTest. by @eamonnmcmanus in #2228

New Contributors

• @bufistov made their first contribution in #1555
• @JamesZBL made their first contribution in #1246
• @xtay2 made their first contribution in #2169
• @deeptimarrivada1 made their first contribution in #2192
• @kb-1000 made their first contribution in #2196
• @BillyGalbreath made their first contribution in #2213
• @staale made their first contribution in #2201

Full Changelog: gson-parent-2.9.1...gson-parent-2.10

Gson 2.9.1

• Make Object and JsonElement deserialization iterative rather than recursive (#1912)
• Added parsing support for enum that has overridden toString() method (#1950)
• Removed support for building Gson with Gradle (#2081)
• Removed obsolete codegen hierarchy (#2099)
• Add support for reflection access filter (#1905)
• Improve TypeToken creation validation (#2072)
• Add explicit support for float in JsonWriter (#2130, #2132)
• Fail when parsing invalid local date (#2134)

Also many small improvements to javadoc.

Gson 2.9.0

The minimum supported Java version changes from 6 to 7.

• Change target Java version to 7 (#2043)
• Put module-info.class into Multi-Release JAR folder (#2013)
• Improve error message when abstract class cannot be constructed (#1814)
• Support EnumMap deserialization (#2071)
• Add LazilyParsedNumber default adapter (#2060)
• Fix JsonReader.hasNext() returning true at end of document (#2061)
• Remove Gradle build support. Build script was outdated and not actively maintained anymore (#2063)
• Add GsonBuilder.disableJdkUnsafe() (#1904)
• Add UPPER_CASE_WITH_UNDERSCORES in FieldNamingPolicy (#2024)
• Fix failing to serialize Collection or Map with inaccessible constructor (#1902)
• Improve TreeTypeAdapter thread-safety (#1976)
• Fix Gson.newJsonWriter ignoring lenient and HTML-safe setting (#1989)
• Delete unused LinkedHashTreeMap (#1992)
• Make default adapters stricter; improve exception messages (#2000)
• Fix FieldNamingPolicy.upperCaseFirstLetter uppercasing non-letter (#2004)

Thanks to our contributors, especially @Marcono1234!

Gson 2.8.9

• Make OSGi bundle's dependency on sun.misc optional (#1993).
• Deprecate Gson.excluder() exposing internal Excluder class (#1986).
• Prevent Java deserialization of internal classes (#1991).
• Improve number strategy implementation (#1987).
• Fix LongSerializationPolicy null handling being inconsistent with Gson (#1990).
• Support arbitrary Number implementation for Object and Number deserialization (#1290).
• Bump proguard-maven-plugin from 2.4.0 to 2.5.1 (#1980).
• Don't exclude static local classes (#1969).
• Fix RuntimeTypeAdapterFactory depending on internal Streams class (#1959).
• Improve Maven build (#1964).
• Make dependency on java.sql optional (#1707).

Gson 2.8.8

• Fixed issue with recursive types (#1390).
• Better behaviour with Java 9+ and Unsafe if there is a security manager (#1712).
• EnumTypeAdapter now works better when ProGuard has obfuscated enum fields (#1495).