Can be replaced with String.repeat()

lib-extra/src/groovy/java/com/diffplug/spotless/extra/glue/groovy/GrEclipseFormatterStepImpl.java

@@ -15,6 +15,8 @@
  */
 package com.diffplug.spotless.extra.glue.groovy;
 
+import static java.lang.System.lineSeparator;
+
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -143,7 +145,7 @@ public String toString() {
 			}
 			for (Throwable error : errors) {
 				error.printStackTrace();
-				string.append(System.lineSeparator());
+				string.append(lineSeparator());
 				string.append(error.getMessage());
 			}
 

lib-extra/src/jdt/java/com/diffplug/spotless/extra/glue/jdt/DefaultJavaElementComparator.java

@@ -347,28 +347,14 @@ public int compare(BodyDeclaration bodyDeclaration1, BodyDeclaration bodyDeclara
 	}
 
 	private static int sortPreservedCategory(int category) {
-		switch (category) {
-		case STATIC_FIELDS_INDEX:
-		case STATIC_INIT_INDEX:
-			return STATIC_FIELDS_INDEX;
-		case FIELDS_INDEX:
-		case INIT_INDEX:
-			return FIELDS_INDEX;
-		default:
-			return category;
-		}
+		return switch (category) {
+			case STATIC_FIELDS_INDEX, STATIC_INIT_INDEX -> STATIC_FIELDS_INDEX;
+			case FIELDS_INDEX, INIT_INDEX -> FIELDS_INDEX;
+			default -> category;
+		};
 	}
 
-	private boolean isSortPreserved(BodyDeclaration bodyDeclaration) {
-		switch (bodyDeclaration.getNodeType()) {
-		case ASTNode.FIELD_DECLARATION:
-		case ASTNode.ENUM_CONSTANT_DECLARATION:
-		case ASTNode.INITIALIZER:
-			return true;
-		default:
-			return false;
-		}
-	}
+	private boolean isSortPreserved(BodyDeclaration bodyDeclaration) {return switch(bodyDeclaration.getNodeType()){case ASTNode.FIELD_DECLARATION,ASTNode.ENUM_CONSTANT_DECLARATION,ASTNode.INITIALIZER->true;default->false;};}
 
 	private int preserveRelativeOrder(BodyDeclaration bodyDeclaration1, BodyDeclaration bodyDeclaration2) {
 		int value1 = (Integer) bodyDeclaration1.getProperty(CompilationUnitSorter.RELATIVE_ORDER);

lib-extra/src/main/java/com/diffplug/spotless/extra/GitAttributesLineEndings.java

@@ -300,15 +300,14 @@ public String getEndingFor(File file) {
 		}
 
 		private static String convertEolToLineEnding(String eol, File file) {
-			switch (eol.toLowerCase(Locale.ROOT)) {
-			case "lf":
-				return LineEnding.UNIX.str();
-			case "crlf":
-				return LineEnding.WINDOWS.str();
-			default:
-				LOGGER.warn(".gitattributes file has unspecified eol value: {} for {}, defaulting to platform native", eol, file);
-				return LineEnding.PLATFORM_NATIVE.str();
-			}
+			return switch (eol.toLowerCase(Locale.ROOT)) {
+				case "lf" -> LineEnding.UNIX.str();
+				case "crlf" -> LineEnding.WINDOWS.str();
+				default -> {
+					LOGGER.warn(".gitattributes file has unspecified eol value: {} for {}, defaulting to platform native", eol, file);
+					yield LineEnding.PLATFORM_NATIVE.str();
+				}
+			};
 		}
 
 		private LineEnding findDefaultLineEnding(Config config) {
@@ -335,14 +334,11 @@ private LineEnding findDefaultLineEnding(Config config) {
 
 		/** Creates a LineEnding from an EOL. */
 		private static LineEnding fromEol(EOL eol) {
-			// @formatter:off
-			switch (eol) {
-			case CRLF:    return LineEnding.WINDOWS;
-			case LF:      return LineEnding.UNIX;
-			case NATIVE:  return LineEnding.PLATFORM_NATIVE;
-			default: throw new IllegalArgumentException("Unknown eol " + eol);
-			}
-			// @formatter:on
+			return switch (eol) {
+				case CRLF -> LineEnding.WINDOWS;
+				case LF -> LineEnding.UNIX;
+				case NATIVE -> LineEnding.PLATFORM_NATIVE;
+			};
 		}
 	}
 

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

@@ -15,6 +15,8 @@
  */
 package com.diffplug.spotless;
 
+import static java.lang.System.lineSeparator;
+
 import java.io.File;
 import java.util.Arrays;
 import java.util.Comparator;
@@ -253,7 +255,7 @@ private String buildUpgradeFormatterMessage(V fmtVersion) {
 		public String toString() {
 			return "%s alternatives:%n".formatted(fmtName)
 					+ jvm2fmtMaxVersion.entrySet().stream().map(
-							e -> "- Version %s requires JVM %d+".formatted(e.getValue(), e.getKey())).collect(Collectors.joining(System.lineSeparator()));
+							e -> "- Version %s requires JVM %d+".formatted(e.getValue(), e.getKey())).collect(Collectors.joining(lineSeparator()));
 		}
 
 		@SuppressFBWarnings("SE_COMPARATOR_SHOULD_BE_SERIALIZABLE")

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

@@ -15,6 +15,8 @@
  */
 package com.diffplug.spotless;
 
+import static java.lang.System.lineSeparator;
+
 import java.io.File;
 import java.io.FileReader;
 import java.io.IOException;
@@ -30,19 +32,20 @@
  * Represents the line endings which should be written by the tool.
  */
 public enum LineEnding {
-	// @formatter:off
 	/** Uses the same line endings as Git, using {@code .gitattributes} and the {@code core.eol} property. */
 	GIT_ATTRIBUTES {
 		/** .gitattributes is path-specific, so you must use {@link LineEnding#createPolicy(File, Supplier)}. */
-		@Override @Deprecated
+		@Override
+		@Deprecated
 		public Policy createPolicy() {
 			return super.createPolicy();
 		}
 	},
 	/** Uses the same line endings as Git, and assumes that every single file being formatted will have the same line ending. */
 	GIT_ATTRIBUTES_FAST_ALLSAME {
 		/** .gitattributes is path-specific, so you must use {@link LineEnding#createPolicy(File, Supplier)}. */
-		@Override @Deprecated
+		@Override
+		@Deprecated
 		public Policy createPolicy() {
 			return super.createPolicy();
 		}
@@ -51,13 +54,12 @@ public Policy createPolicy() {
 	PLATFORM_NATIVE,
 	/** {@code \r\n} */
 	WINDOWS,
-    /** {@code \n} */
-    UNIX,
-    /** {@code \r} */
-    MAC_CLASSIC,
-    /** preserve the line ending of the first line (no matter which format) */
-    PRESERVE;
-	// @formatter:on
+	/** {@code \n} */
+	UNIX,
+	/** {@code \r} */
+	MAC_CLASSIC,
+	/** preserve the line ending of the first line (no matter which format) */
+	PRESERVE;
 
 	/** Returns a {@link Policy} appropriate for files which are contained within the given rootFolder. */
 	public Policy createPolicy(File projectDir, Supplier<Iterable<File>> toFormat) {
@@ -80,21 +82,21 @@ public Policy createPolicy(File projectDir, Supplier<Iterable<File>> toFormat) {
 		}
 	}
 
-	// @formatter:off
 	/** Should use {@link #createPolicy(File, Supplier)} instead, but this will work iff its a path-independent LineEnding policy. */
 	public Policy createPolicy() {
-		switch (this) {
-		case PLATFORM_NATIVE:	return _PLATFORM_NATIVE_POLICY;
-		case WINDOWS:			return WINDOWS_POLICY;
-		case UNIX:				return UNIX_POLICY;
-		case MAC_CLASSIC:		return MAC_CLASSIC_POLICY;
-		case PRESERVE:			return PRESERVE_POLICY;
-		default:	throw new UnsupportedOperationException(this + " is a path-specific line ending.");
-		}
+		return switch (this) {
+			case PLATFORM_NATIVE -> _PLATFORM_NATIVE_POLICY;
+			case WINDOWS -> WINDOWS_POLICY;
+			case UNIX -> UNIX_POLICY;
+			case MAC_CLASSIC -> MAC_CLASSIC_POLICY;
+			case PRESERVE -> PRESERVE_POLICY;
+			default -> throw new UnsupportedOperationException(this + " is a path-specific line ending.");
+		};
 	}
 
 	static class ConstantLineEndingPolicy extends NoLambda.EqualityBasedOnSerialization implements Policy {
-		@Serial private static final long serialVersionUID = 1L;
+		@Serial
+		private static final long serialVersionUID = 1L;
 
 		final String lineEnding;
 
@@ -109,50 +111,51 @@ public String getEndingFor(File file) {
 	}
 
 	static class PreserveLineEndingPolicy extends NoLambda.EqualityBasedOnSerialization implements Policy {
-		@Serial private static final long serialVersionUID = 2L;
-
-        @Override
-        public String getEndingFor(File file) {
-            // assume US-ASCII encoding (only line ending characters need to be decoded anyways)
-            try (Reader reader = new FileReader(file, StandardCharsets.US_ASCII)) {
-                return getEndingFor(reader);
-            } catch (IOException e) {
-                throw new IllegalArgumentException("Could not determine line ending of file: " + file, e);
-            }
-        }
-
-        static String getEndingFor(Reader reader) throws IOException {
-            char previousCharacter = 0;
-            char currentCharacter = 0;
-            int readResult;
-            while ((readResult = reader.read()) != -1) {
-                currentCharacter = (char) readResult;
-                if (currentCharacter == '\n') {
-                    if (previousCharacter == '\r') {
-                        return WINDOWS.str();
-                    } else {
-                        return UNIX.str();
-                    }
-                } else {
-                    if (previousCharacter == '\r') {
-                        return MAC_CLASSIC.str();
-                    }
-                }
-                previousCharacter = currentCharacter;
-            }
-            if (previousCharacter == '\r') {
-                return MAC_CLASSIC.str();
-            }
-            // assume UNIX line endings if no line ending was found
-            return UNIX.str();
-        }
+		@Serial
+		private static final long serialVersionUID = 2L;
+
+		@Override
+		public String getEndingFor(File file) {
+			// assume US-ASCII encoding (only line ending characters need to be decoded anyways)
+			try (Reader reader = new FileReader(file, StandardCharsets.US_ASCII)) {
+				return getEndingFor(reader);
+			} catch (IOException e) {
+				throw new IllegalArgumentException("Could not determine line ending of file: " + file, e);
+			}
+		}
+
+		static String getEndingFor(Reader reader) throws IOException {
+			char previousCharacter = 0;
+			char currentCharacter;
+			int readResult;
+			while ((readResult = reader.read()) != -1) {
+				currentCharacter = (char) readResult;
+				if (currentCharacter == '\n') {
+					if (previousCharacter == '\r') {
+						return WINDOWS.str();
+					} else {
+						return UNIX.str();
+					}
+				} else {
+					if (previousCharacter == '\r') {
+						return MAC_CLASSIC.str();
+					}
+				}
+				previousCharacter = currentCharacter;
+			}
+			if (previousCharacter == '\r') {
+				return MAC_CLASSIC.str();
+			}
+			// assume UNIX line endings if no line ending was found
+			return UNIX.str();
+		}
 	}
 
 	private static final Policy WINDOWS_POLICY = new ConstantLineEndingPolicy(WINDOWS.str());
 	private static final Policy UNIX_POLICY = new ConstantLineEndingPolicy(UNIX.str());
-    private static final Policy MAC_CLASSIC_POLICY = new ConstantLineEndingPolicy(MAC_CLASSIC.str());
-    private static final Policy PRESERVE_POLICY = new PreserveLineEndingPolicy();
-	private static final String _PLATFORM_NATIVE = System.getProperty("line.separator");
+	private static final Policy MAC_CLASSIC_POLICY = new ConstantLineEndingPolicy(MAC_CLASSIC.str());
+	private static final Policy PRESERVE_POLICY = new PreserveLineEndingPolicy();
+	private static final String _PLATFORM_NATIVE = lineSeparator();
 	private static final Policy _PLATFORM_NATIVE_POLICY = new ConstantLineEndingPolicy(_PLATFORM_NATIVE);
 	private static final boolean NATIVE_IS_WIN = _PLATFORM_NATIVE.equals(WINDOWS.str());
 
@@ -169,15 +172,14 @@ public static boolean nativeIsWin() {
 
 	/** Returns the standard line ending for this policy. */
 	public String str() {
-		switch (this) {
-		case PLATFORM_NATIVE:	return _PLATFORM_NATIVE;
-		case WINDOWS:			return "\r\n";
-		case UNIX:				return "\n";
-		case MAC_CLASSIC:		return "\r";
-		default:	throw new UnsupportedOperationException(this + " is a path-specific line ending.");
-		}
+		return switch (this) {
+			case PLATFORM_NATIVE -> _PLATFORM_NATIVE;
+			case WINDOWS -> "\r\n";
+			case UNIX -> "\n";
+			case MAC_CLASSIC -> "\r";
+			default -> throw new UnsupportedOperationException(this + " is a path-specific line ending.");
+		};
 	}
-	// @formatter:on
 
 	/** A policy for line endings which can vary based on the specific file being requested. */
 	public interface Policy extends Serializable, NoLambda {

lib/src/main/java/com/diffplug/spotless/generic/EndWithNewlineStep.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 DiffPlug
+ * Copyright 2016-2025 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -52,10 +52,7 @@ private static String format(String rawUnix) {
 		} else if (lastContentCharacter == rawUnix.length() - 2 && rawUnix.charAt(rawUnix.length() - 1) == '\n') {
 			return rawUnix;
 		} else {
-			StringBuilder builder = new StringBuilder(lastContentCharacter + 2);
-			builder.append(rawUnix, 0, lastContentCharacter + 1);
-			builder.append('\n');
-			return builder.toString();
+			return rawUnix.substring(0, lastContentCharacter + 1) + '\n';
 		}
 	}
 }

lib/src/main/java/com/diffplug/spotless/generic/IndentStep.java

@@ -104,14 +104,10 @@ String format(String raw) {
 				if (numSpaces > 0) {
 					switch (state.type) {
 					case SPACE:
-						for (int i = 0; i < numSpaces; i++) {
-							builder.append(' ');
-						}
+						builder.append(" ".repeat(numSpaces));
 						break;
 					case TAB:
-						for (int i = 0; i < numSpaces / state.numSpacesPerTab; i++) {
-							builder.append('\t');
-						}
+						builder.append("\t".repeat(numSpaces / state.numSpacesPerTab));
 						if (mightBeMultiLineComment && (numSpaces % state.numSpacesPerTab == 1)) {
 							builder.append(' ');
 						}

lib/src/main/java/com/diffplug/spotless/groovy/RemoveSemicolonsStep.java

@@ -15,6 +15,8 @@
  */
 package com.diffplug.spotless.groovy;
 
+import static java.lang.System.lineSeparator;
+
 import java.io.BufferedReader;
 import java.io.Serial;
 import java.io.Serializable;
@@ -54,7 +56,7 @@ FormatterFunc toFormatter() {
 					String line;
 					while ((line = reader.readLine()) != null) {
 						result.append(removeSemicolon(line));
-						result.append(System.lineSeparator());
+						result.append(lineSeparator());
 					}
 					return result.toString();
 				}

lib/src/main/java/com/diffplug/spotless/pom/SortPomCfg.java

@@ -15,6 +15,8 @@
  */
 package com.diffplug.spotless.pom;
 
+import static java.lang.System.lineSeparator;
+
 import java.io.Serial;
 import java.io.Serializable;
 
@@ -27,7 +29,7 @@ public class SortPomCfg implements Serializable {
 
 	public String encoding = "UTF-8";
 
-	public String lineSeparator = System.getProperty("line.separator");
+	public String lineSeparator = lineSeparator();
 
 	public boolean expandEmptyElements;