Java best practices

Usage

This recipe has no required configuration options. You’ll need the Moderne CLI configured before running the command below.

mod run . --recipe org.openrewrite.java.migrate.JavaBestPractices

If the recipe isn’t available locally, install it with:

mod config recipes jar install org.openrewrite.recipe:rewrite-migrate-java:3.41.0

Definition

This recipe runs the following recipes in order.

• Migrate to Java 25org.openrewrite.java.migrate.UpgradeToJava25
• Migrate public static void main(String[] args) to instance void main()org.openrewrite.java.migrate.lang.MigrateMainMethodToInstanceMain
• Extract complex super(..) and this(..) arguments into local variablesorg.openrewrite.java.migrate.lang.ExtractExplicitConstructorInvocationArguments
• Replace unused variables with underscoreorg.openrewrite.java.migrate.lang.ReplaceUnusedVariablesWithUnderscore
• Use text blocksorg.openrewrite.java.migrate.lang.UseTextBlocks
• Prefer String.formatted(Object...)org.openrewrite.java.migrate.lang.StringFormatted
• Prefer the Java standard library instead of Guavaorg.openrewrite.java.migrate.guava.NoGuava
• Prefer the Java standard library instead of Joda-Timeorg.openrewrite.java.joda.time.NoJodaTime
• JSpecify best practicesorg.openrewrite.java.jspecify.JSpecifyBestPractices
• Use var for variables initialized with type castsorg.openrewrite.java.migrate.lang.var.UseVarForTypeCast
• Use var for constructor call assignmentsorg.openrewrite.java.migrate.lang.var.UseVarForConstructors
• Apply var to Generic Constructorsorg.openrewrite.java.migrate.lang.var.UseVarForGenericsConstructors
• Apply var to generic method invocationsorg.openrewrite.java.migrate.lang.var.UseVarForGenericMethodInvocations
• Use var for primitive and String variablesorg.openrewrite.java.migrate.lang.var.UseVarForPrimitive
• Use modernized java.util APIsorg.openrewrite.java.migrate.util.JavaUtilAPIs
• Equals avoids nullorg.openrewrite.staticanalysis.EqualsAvoidsNull
• Add missing @Override to overriding and implementing methodsorg.openrewrite.staticanalysis.MissingOverrideAnnotation
• Week Year (YYYY) should not be used for date formattingorg.openrewrite.staticanalysis.ReplaceWeekYearWithYear
• hashCode() should not be called on array instancesorg.openrewrite.staticanalysis.RemoveHashCodeCallsFromArrayInstances
• Remove toString() calls on arraysorg.openrewrite.staticanalysis.RemoveToStringCallsFromArrayInstances
• Replaces Object.notify() with Object.notifyAll()org.openrewrite.staticanalysis.UseObjectNotifyAll
• Remove garbage collection invocationsorg.openrewrite.staticanalysis.RemoveCallsToSystemGc
• Remove Object.finalize() invocationsorg.openrewrite.staticanalysis.RemoveCallsToObjectFinalize
• URL Equals and Hash Codeorg.openrewrite.staticanalysis.URLEqualsHashCodeRecipes
• Simplify lambda blocks to expressionsorg.openrewrite.staticanalysis.LambdaBlockToExpression
• Use method references in lambdaorg.openrewrite.staticanalysis.ReplaceLambdaWithMethodReference
• Use the diamond operatororg.openrewrite.staticanalysis.UseDiamondOperator
• Remove unnecessary parenthesesorg.openrewrite.staticanalysis.UnnecessaryParentheses
• Remove redundant null checks before instanceoforg.openrewrite.staticanalysis.RemoveRedundantNullCheckBeforeInstanceof
• Replace StringBuilder#append with Stringorg.openrewrite.staticanalysis.ReplaceStringBuilderWithString
• Use Collection interfacesorg.openrewrite.staticanalysis.UseCollectionInterfaces
• Enum values should be compared with "=="org.openrewrite.staticanalysis.CompareEnumsWithEqualityOperator
• Combine semantically equal catch blocksorg.openrewrite.staticanalysis.CombineSemanticallyEqualCatchBlocks
• Use String::replace() when first parameter is not a real regular expressionorg.openrewrite.staticanalysis.UseStringReplace
• Use StandardCharset constantsorg.openrewrite.staticanalysis.UseStandardCharset
• Use System.lineSeparator()org.openrewrite.staticanalysis.UseSystemLineSeparator
• Remove redundant castsorg.openrewrite.staticanalysis.RemoveRedundantTypeCast
• Replace java.util.Stack with java.util.Dequeorg.openrewrite.staticanalysis.ReplaceStackWithDeque
• Replace invocations of Collections#sort(List, Comparator) with List#sort(Comparator)org.openrewrite.staticanalysis.UseListSort
• Use String.contentEquals(CharSequence) instead of String.equals(CharSequence.toString())org.openrewrite.staticanalysis.EqualsToContentEquals
• Convert Javadoc to Markdown documentation commentsorg.openrewrite.java.migrate.lang.JavadocToMarkdownDocComment
• Remove unused importsorg.openrewrite.java.RemoveUnusedImports

Data tables

Structured output this recipe can produce.

• Maven metadata failuresAttempts to resolve maven metadata that failed.org.openrewrite.maven.table.MavenMetadataFailures
• Source files that had resultsSource files that were modified by the recipe run.org.openrewrite.table.SourcesFileResults
• Source files that had search resultsSearch results that were found during the recipe run.org.openrewrite.table.SearchResults
• Source files that errored on a recipeThe details of all errors produced by a recipe run.org.openrewrite.table.SourcesFileErrors
• Recipe performanceStatistics used in analyzing the performance of recipes.org.openrewrite.table.RecipeRunStats