Add maxLineLength option to googleJavaFormat step (requires gjf 1.37.0+)

CHANGES.md

@@ -11,6 +11,9 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 
 ## [Unreleased]
 
+### Features
+- `googleJavaFormat` gained a `maxLineLength` option, which overrides the 100-column limit prescribed by the GOOGLE and AOSP styles. It requires `google-java-format` `1.37.0` or later, and the step now also works at all with `1.37.0+` (upstream changed `JavaFormatterOptions.Style` from an enum to a record in `1.37.0`). ([#3151](https://github.com/diffplug/spotless/issues/3151))
+
 ## [4.10.4] - 2026-10-08
 
 ### Changes

lib/src/googleJavaFormat/java/com/diffplug/spotless/glue/java/GoogleJavaFormatFormatterFunc.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023 DiffPlug
+ * Copyright 2023-2026 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,8 @@
  */
 package com.diffplug.spotless.glue.java;
 
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
 import java.util.Objects;
 
 import javax.annotation.Nonnull;
@@ -46,19 +48,65 @@ public class GoogleJavaFormatFormatterFunc implements FormatterFunc {
 
 	private final boolean reorderImports;
 
-	public GoogleJavaFormatFormatterFunc(@Nonnull String version, @Nonnull String style, boolean reflowStrings, boolean reorderImports, boolean formatJavadoc) {
+	public GoogleJavaFormatFormatterFunc(@Nonnull String version, @Nonnull String style, boolean reflowStrings, boolean reorderImports, boolean formatJavadoc, int maxLineLength) {
 		this.version = Objects.requireNonNull(version);
-		this.formatterStyle = Style.valueOf(Objects.requireNonNull(style));
+		this.formatterStyle = toStyle(style);
 		this.reflowStrings = reflowStrings;
 		this.reorderImports = reorderImports;
 
-		JavaFormatterOptions.Builder builder = JavaFormatterOptions.builder().style(formatterStyle);
+		Style effectiveStyle = formatterStyle;
+		if (maxLineLength > 0) {
+			effectiveStyle = withMaxLineLength(formatterStyle, maxLineLength, version);
+		}
+		JavaFormatterOptions.Builder builder = JavaFormatterOptions.builder().style(effectiveStyle);
 		if (!formatJavadoc) {
 			builder = builder.formatJavadoc(false);
 		}
 		this.formatter = new Formatter(builder.build());
 	}
 
+	/**
+	 * Parses a style name without calling {@code Style.valueOf}, which existed only while
+	 * {@code Style} was an enum (google-java-format {@literal <=} 1.36); since 1.37 it is a record,
+	 * but the {@code GOOGLE} and {@code AOSP} constants are present in both.
+	 */
+	@Nonnull
+	private static Style toStyle(@Nonnull String style) {
+		switch (Objects.requireNonNull(style)) {
+		case "GOOGLE":
+			return Style.GOOGLE;
+		case "AOSP":
+			return Style.AOSP;
+		default:
+			throw new IllegalArgumentException("style must be GOOGLE or AOSP, but was: " + style);
+		}
+	}
+
+	/**
+	 * Sets the column limit on the style's builder. That builder exists only in google-java-format
+	 * 1.37.0+, while this glue code is compiled against 1.28.0 so that it keeps working on older
+	 * versions, hence the reflection (https://github.com/diffplug/spotless/issues/3151).
+	 * Methods are looked up on the public {@code Style$Builder} type rather than on the runtime
+	 * class of the builder, because the runtime class generated by AutoBuilder is package-private.
+	 */
+	@Nonnull
+	private static Style withMaxLineLength(@Nonnull Style style, int maxLineLength, @Nonnull String version) {
+		try {
+			Method createBuilder = Style.class.getMethod("builder");
+			Class<?> builderType = createBuilder.getReturnType();
+			Object builder = createBuilder.invoke(null);
+			builder = builderType.getMethod(style == Style.AOSP ? "aosp" : "google").invoke(builder);
+			builder = builderType.getMethod("maxLineLength", int.class).invoke(builder, maxLineLength);
+			return (Style) builderType.getMethod("build").invoke(builder);
+		} catch (NoSuchMethodException e) {
+			throw new IllegalArgumentException(
+					"maxLineLength requires google-java-format 1.37.0 or later (you are using " + version + ")", e);
+		} catch (IllegalAccessException | InvocationTargetException e) {
+			Throwable cause = e instanceof InvocationTargetException ? e.getCause() : e;
+			throw new IllegalArgumentException("Failed to apply maxLineLength " + maxLineLength, cause);
+		}
+	}
+
 	@Override
 	@Nonnull
 	public String apply(@Nonnull String input) throws Exception {

lib/src/main/java/com/diffplug/spotless/java/GoogleJavaFormatStep.java

@@ -18,6 +18,7 @@
 import java.io.Serial;
 import java.io.Serializable;
 import java.lang.reflect.Constructor;
+import java.util.Arrays;
 import java.util.Objects;
 
 import com.diffplug.spotless.FormatterFunc;
@@ -34,6 +35,10 @@ public final class GoogleJavaFormatStep implements Serializable {
 	private static final boolean DEFAULT_REFLOW_LONG_STRINGS = false;
 	private static final boolean DEFAULT_REORDER_IMPORTS = false;
 	private static final boolean DEFAULT_FORMAT_JAVADOC = true;
+	/** 0 means "not set", i.e. use whatever column limit the formatter's style prescribes. */
+	private static final int DEFAULT_MAX_LINE_LENGTH = 0;
+	/** The first version which made `JavaFormatterOptions.Style` configurable, see [#3151](https://github.com/diffplug/spotless/issues/3151). */
+	static final String MIN_VERSION_FOR_MAX_LINE_LENGTH = "1.37.0";
 	private static final String NAME = "google-java-format";
 	private static final String MAVEN_COORDINATE = "com.google.googlejavaformat:google-java-format";
 
@@ -44,19 +49,22 @@ public final class GoogleJavaFormatStep implements Serializable {
 	private final boolean reflowLongStrings;
 	private final boolean reorderImports;
 	private final boolean formatJavadoc;
+	private final int maxLineLength;
 
 	private GoogleJavaFormatStep(JarState.Promised jarState,
 			String version,
 			String style,
 			boolean reflowLongStrings,
 			boolean reorderImports,
-			boolean formatJavadoc) {
+			boolean formatJavadoc,
+			int maxLineLength) {
 		this.jarState = jarState;
 		this.version = version;
 		this.style = style;
 		this.reflowLongStrings = reflowLongStrings;
 		this.reorderImports = reorderImports;
 		this.formatJavadoc = formatJavadoc;
+		this.maxLineLength = maxLineLength;
 	}
 
 	/** Creates a step which formats everything - code, import order, and unused imports. */
@@ -89,23 +97,37 @@ public static FormatterStep create(String groupArtifact, String version, String
 
 	/** Creates a step which formats everything - groupArtifact, code, import order, and unused imports - and optionally reflows long strings. */
 	public static FormatterStep create(String groupArtifact, String version, String style, Provisioner provisioner, boolean reflowLongStrings, boolean reorderImports, boolean formatJavadoc) {
-		return createInternally(NAME, groupArtifact, version, style, provisioner, reflowLongStrings, reorderImports, formatJavadoc, false);
+		return create(groupArtifact, version, style, provisioner, reflowLongStrings, reorderImports, formatJavadoc, DEFAULT_MAX_LINE_LENGTH);
+	}
+
+	/**
+	 * Creates a step which formats everything - groupArtifact, code, import order, and unused imports - and optionally reflows long strings.
+	 * A positive {@code maxLineLength} overrides the column limit prescribed by the style, and requires google-java-format {@code 1.37.0} or later.
+	 */
+	public static FormatterStep create(String groupArtifact, String version, String style, Provisioner provisioner, boolean reflowLongStrings, boolean reorderImports, boolean formatJavadoc, int maxLineLength) {
+		return createInternally(NAME, groupArtifact, version, style, provisioner, reflowLongStrings, reorderImports, formatJavadoc, maxLineLength, false);
 	}
 
 	static FormatterStep createRemoveUnusedImportsOnly(Provisioner provisioner) {
-		return createInternally(RemoveUnusedImportsStep.NAME, MAVEN_COORDINATE, defaultVersion(), defaultStyle(), provisioner, defaultReflowLongStrings(), defaultReorderImports(), defaultFormatJavadoc(), true);
+		return createInternally(RemoveUnusedImportsStep.NAME, MAVEN_COORDINATE, defaultVersion(), defaultStyle(), provisioner, defaultReflowLongStrings(), defaultReorderImports(), defaultFormatJavadoc(), DEFAULT_MAX_LINE_LENGTH, true);
 	}
 
-	private static FormatterStep createInternally(String name, String groupArtifact, String version, String style, Provisioner provisioner, boolean reflowLongStrings, boolean reorderImports, boolean formatJavadoc, boolean removeImports) {
+	private static FormatterStep createInternally(String name, String groupArtifact, String version, String style, Provisioner provisioner, boolean reflowLongStrings, boolean reorderImports, boolean formatJavadoc, int maxLineLength, boolean removeImports) {
 		Objects.requireNonNull(groupArtifact, "groupArtifact");
 		if (groupArtifact.chars().filter(ch -> ch == ':').count() != 1) {
 			throw new IllegalArgumentException("groupArtifact must be in the form 'groupId:artifactId'");
 		}
 		Objects.requireNonNull(version, "version");
 		Objects.requireNonNull(style, "style");
 		Objects.requireNonNull(provisioner, "provisioner");
+		if (maxLineLength < 0) {
+			throw new IllegalArgumentException("maxLineLength must be positive, but was: " + maxLineLength);
+		}
+		if (maxLineLength > 0 && compareVersions(version, MIN_VERSION_FOR_MAX_LINE_LENGTH) < 0) {
+			throw new IllegalArgumentException("maxLineLength requires google-java-format " + MIN_VERSION_FOR_MAX_LINE_LENGTH + " or later (you are using " + version + ")");
+		}
 
-		GoogleJavaFormatStep step = new GoogleJavaFormatStep(JarState.promise(() -> JarState.from(groupArtifact + ":" + version, provisioner)), version, style, reflowLongStrings, reorderImports, formatJavadoc);
+		GoogleJavaFormatStep step = new GoogleJavaFormatStep(JarState.promise(() -> JarState.from(groupArtifact + ":" + version, provisioner)), version, style, reflowLongStrings, reorderImports, formatJavadoc, maxLineLength);
 		if (removeImports) {
 			return FormatterStep.create(name,
 					step,
@@ -150,8 +172,36 @@ public static boolean defaultFormatJavadoc() {
 		return DEFAULT_FORMAT_JAVADOC;
 	}
 
+	public static int defaultMaxLineLength() {
+		return DEFAULT_MAX_LINE_LENGTH;
+	}
+
+	/** Compares dotted numeric versions, e.g. {@code compareVersions("1.36.1", "1.37.0") < 0}. */
+	private static int compareVersions(String left, String right) {
+		int[] lhs = parseVersion(left);
+		int[] rhs = parseVersion(right);
+		int numberOfElements = Math.max(lhs.length, rhs.length);
+		lhs = Arrays.copyOf(lhs, numberOfElements);
+		rhs = Arrays.copyOf(rhs, numberOfElements);
+		for (int i = 0; i < numberOfElements; i++) {
+			if (lhs[i] != rhs[i]) {
+				return lhs[i] > rhs[i] ? 1 : -1;
+			}
+		}
+		return 0;
+	}
+
+	private static int[] parseVersion(String version) {
+		try {
+			String withoutSuffix = version.endsWith("-SNAPSHOT") ? version.substring(0, version.length() - "-SNAPSHOT".length()) : version;
+			return Arrays.stream(withoutSuffix.split("\\.")).mapToInt(Integer::parseInt).toArray();
+		} catch (Exception e) {
+			throw new IllegalArgumentException("Not a semantic version: " + version, e);
+		}
+	}
+
 	private State equalityState() {
-		return new State(version, style, jarState.get(), reflowLongStrings, reorderImports, formatJavadoc);
+		return new State(version, style, jarState.get(), reflowLongStrings, reorderImports, formatJavadoc, maxLineLength);
 	}
 
 	private static final class State implements Serializable {
@@ -164,13 +214,15 @@ private static final class State implements Serializable {
 		private final boolean reflowLongStrings;
 		private final boolean reorderImports;
 		private final boolean formatJavadoc;
+		private final int maxLineLength;
 
 		State(String version,
 				String style,
 				JarState jarState,
 				boolean reflowLongStrings,
 				boolean reorderImports,
-				boolean formatJavadoc) {
+				boolean formatJavadoc,
+				int maxLineLength) {
 			JVM_SUPPORT.assertFormatterSupported(version);
 			ModuleHelper.doOpenInternalPackagesIfRequired();
 			this.jarState = jarState;
@@ -179,13 +231,14 @@ private static final class State implements Serializable {
 			this.reflowLongStrings = reflowLongStrings;
 			this.reorderImports = reorderImports;
 			this.formatJavadoc = formatJavadoc;
+			this.maxLineLength = maxLineLength;
 		}
 
 		FormatterFunc createFormat() throws Exception {
 			final ClassLoader classLoader = jarState.getClassLoader();
 			Class<?> formatterFunc = classLoader.loadClass("com.diffplug.spotless.glue.java.GoogleJavaFormatFormatterFunc");
-			Constructor<?> constructor = formatterFunc.getConstructor(String.class, String.class, boolean.class, boolean.class, boolean.class);
-			FormatterFunc googleJavaFormatFormatterFunc = (FormatterFunc) constructor.newInstance(version, style, reflowLongStrings, reorderImports, formatJavadoc);
+			Constructor<?> constructor = formatterFunc.getConstructor(String.class, String.class, boolean.class, boolean.class, boolean.class, int.class);
+			FormatterFunc googleJavaFormatFormatterFunc = (FormatterFunc) constructor.newInstance(version, style, reflowLongStrings, reorderImports, formatJavadoc, maxLineLength);
 
 			return JVM_SUPPORT.suggestLaterVersionOnError(version, googleJavaFormatFormatterFunc);
 		}

plugin-gradle/CHANGES.md

@@ -4,6 +4,9 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 
 ## [Unreleased]
 
+### Features
+- `googleJavaFormat` gained `maxLineLength(int)`, which overrides the 100-column limit prescribed by the GOOGLE and AOSP styles. It requires `google-java-format` `1.37.0` or later. ([#3151](https://github.com/diffplug/spotless/issues/3151))
+
 ## [8.10.4] - 2026-10-08
 
 ### Changes

plugin-gradle/README.md

@@ -380,8 +380,9 @@ spotless {
     googleJavaFormat()
     // optional: you can specify a specific version (>= 1.8) and/or switch to AOSP style
     //   and/or reflow long strings
+    //   and/or override the 100-column limit (requires google-java-format 1.37.0+)
     //   and/or use custom group artifact (you probably don't need this)
-    googleJavaFormat('1.8').aosp().reflowLongStrings().formatJavadoc(false).reorderImports(false).groupArtifact('com.google.googlejavaformat:google-java-format')
+    googleJavaFormat('1.8').aosp().reflowLongStrings().maxLineLength(120).formatJavadoc(false).reorderImports(false).groupArtifact('com.google.googlejavaformat:google-java-format')
 ```
 
 ### palantir-java-format

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/JavaExtension.java

@@ -211,6 +211,7 @@ public class GoogleJavaFormatConfig {
 		boolean reflowLongStrings;
 		boolean reorderImports;
 		boolean formatJavadoc = true;
+		int maxLineLength = GoogleJavaFormatStep.defaultMaxLineLength();
 
 		GoogleJavaFormatConfig(String version) {
 			this.version = Objects.requireNonNull(version);
@@ -261,6 +262,16 @@ public GoogleJavaFormatConfig formatJavadoc(boolean formatJavadoc) {
 			return this;
 		}
 
+		/**
+		 * Overrides the column limit prescribed by the style (100 for both GOOGLE and AOSP).
+		 * Requires google-java-format 1.37.0 or later.
+		 */
+		public GoogleJavaFormatConfig maxLineLength(int maxLineLength) {
+			this.maxLineLength = maxLineLength;
+			replaceStep(createStep());
+			return this;
+		}
+
 		private FormatterStep createStep() {
 			return GoogleJavaFormatStep.create(
 					groupArtifact,
@@ -269,7 +280,8 @@ private FormatterStep createStep() {
 					provisioner(),
 					reflowLongStrings,
 					reorderImports,
-					formatJavadoc);
+					formatJavadoc,
+					maxLineLength);
 		}
 	}
 

plugin-gradle/src/test/java/com/diffplug/gradle/spotless/GoogleJavaFormatIntegrationTest.java

@@ -15,6 +15,8 @@
  */
 package com.diffplug.gradle.spotless;
 
+import static org.junit.jupiter.api.Assumptions.assumeTrue;
+
 import java.io.IOException;
 
 import org.junit.jupiter.api.Test;
@@ -101,4 +103,28 @@ void integrationWithSkipJavadocFormatting() throws IOException {
 				"googleJavaFormat()");
 		checkRunsThenUpToDate();
 	}
+
+	@Test
+	void integrationWithMaxLineLength() throws IOException {
+		assumeTrue(Jvm.version() >= 21, "google-java-format 1.37.0 requires JVM 21+");
+
+		setFile("build.gradle").toLines(
+				"plugins {",
+				"    id 'com.diffplug.spotless'",
+				"}",
+				"repositories { mavenCentral() }",
+				"",
+				"spotless {",
+				"    java {",
+				"        target file('test.java')",
+				"        googleJavaFormat('1.37.0').maxLineLength(240)",
+				"    }",
+				"}");
+
+		setFile("test.java").toResource("java/googlejavaformat/JavaCodeUnformatted.test");
+		gradleRunner().withArguments("spotlessApply").build();
+		assertFile("test.java").sameAsResource("java/googlejavaformat/JavaCodeFormattedMaxLineLength240.test");
+
+		checkRunsThenUpToDate();
+	}
 }

plugin-maven/CHANGES.md

@@ -4,6 +4,9 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 
 ## [Unreleased]
 
+### Features
+- `<googleJavaFormat>` gained a `<maxLineLength>` parameter, which overrides the 100-column limit prescribed by the GOOGLE and AOSP styles. It requires `google-java-format` `1.37.0` or later. ([#3151](https://github.com/diffplug/spotless/issues/3151))
+
 ## [3.10.4] - 2026-10-08
 
 ### Changes

plugin-maven/README.md

@@ -343,6 +343,7 @@ Types in `java.lang` and in the file's own package are shortened without adding
   <version>1.8</version>                      <!-- optional, 1.8 is the minimum supported version for Java 11 -->
   <style>GOOGLE</style>                       <!-- or AOSP (optional) -->
   <reflowLongStrings>true</reflowLongStrings> <!-- optional -->
+  <maxLineLength>120</maxLineLength>          <!-- optional, requires google-java-format 1.37.0+ -->
   <formatJavadoc>false</formatJavadoc>        <!-- optional -->
   <reorderImports>false</reorderImports>.     <!-- optional -->
   <!-- optional: custom group artifact (you probably don't need this) -->

plugin-maven/src/main/java/com/diffplug/spotless/maven/java/GoogleJavaFormat.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2023 DiffPlug
+ * Copyright 2016-2026 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -41,6 +41,9 @@ public class GoogleJavaFormat implements FormatterStepFactory {
 	@Parameter
 	private Boolean formatJavadoc;
 
+	@Parameter
+	private Integer maxLineLength;
+
 	@Override
 	public FormatterStep newFormatterStep(FormatterStepConfig config) {
 		String groupArtifact = this.groupArtifact != null ? this.groupArtifact : GoogleJavaFormatStep.defaultGroupArtifact();
@@ -49,6 +52,7 @@ public FormatterStep newFormatterStep(FormatterStepConfig config) {
 		boolean reflowLongStrings = this.reflowLongStrings != null ? this.reflowLongStrings : GoogleJavaFormatStep.defaultReflowLongStrings();
 		boolean reorderImports = this.reorderImports != null ? this.reorderImports : GoogleJavaFormatStep.defaultReorderImports();
 		boolean formatJavadoc = this.formatJavadoc != null ? this.formatJavadoc : GoogleJavaFormatStep.defaultFormatJavadoc();
-		return GoogleJavaFormatStep.create(groupArtifact, version, style, config.getProvisioner(), reflowLongStrings, reorderImports, formatJavadoc);
+		int maxLineLength = this.maxLineLength != null ? this.maxLineLength : GoogleJavaFormatStep.defaultMaxLineLength();
+		return GoogleJavaFormatStep.create(groupArtifact, version, style, config.getProvisioner(), reflowLongStrings, reorderImports, formatJavadoc, maxLineLength);
 	}
 }