refactor: Equals avoids null

timtebeek · TeamModerne · app · commit 6eca13a09558 · 2025-07-30T21:05:14.000Z
Use this link to re-run the recipe: https://app.moderne.io/recipes/org.openrewrite.staticanalysis.EqualsAvoidsNull?organizationId=ODQ2MGExMTUtNDg0My00N2EwLTgzMGMtNGE1NGExMTBmZDkw Co-authored-by: Moderne <team@moderne.io>
diff --git a/src/main/java/org/openrewrite/staticanalysis/ChainStringBuilderAppendCalls.java b/src/main/java/org/openrewrite/staticanalysis/ChainStringBuilderAppendCalls.java
@@ -94,7 +94,7 @@ public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, Execu
                                 appendToString = true;
                             } else if ((exp instanceof J.Identifier || exp instanceof J.MethodInvocation) && exp.getType() != null) {
                                 JavaType.FullyQualified fullyQualified = TypeUtils.asFullyQualified(exp.getType());
-                                if (fullyQualified != null && fullyQualified.getFullyQualifiedName().equals("java.lang.String")) {
+                                if (fullyQualified != null && "java.lang.String".equals(fullyQualified.getFullyQualifiedName())) {
                                     addToGroups(group, groups);
                                     appendToString = true;
                                 }
diff --git a/src/main/java/org/openrewrite/staticanalysis/DefaultComesLastVisitor.java b/src/main/java/org/openrewrite/staticanalysis/DefaultComesLastVisitor.java
@@ -214,7 +214,7 @@ private boolean isDefaultCaseLastOrNotPresent(J.Switch switch_) {
 
     private boolean isDefaultCase(J.Case case_) {
         J elem = case_.getCaseLabels().get(0);
-        return elem instanceof J.Identifier && ((J.Identifier) elem).getSimpleName().equals("default");
+        return elem instanceof J.Identifier && "default".equals(((J.Identifier) elem).getSimpleName());
     }
 
 }
diff --git a/src/main/java/org/openrewrite/staticanalysis/ExplicitLambdaArgumentTypes.java b/src/main/java/org/openrewrite/staticanalysis/ExplicitLambdaArgumentTypes.java
@@ -189,7 +189,7 @@ private J.VariableDeclarations maybeAddTypeExpression(J.VariableDeclarations mul
             if (type instanceof JavaType.GenericTypeVariable) {
                 JavaType.GenericTypeVariable genericType = (JavaType.GenericTypeVariable) type;
 
-                if (!genericType.getName().equals("?")) {
+                if (!"?".equals(genericType.getName())) {
                     return new J.Identifier(Tree.randomId(),
                             space,
                             Markers.EMPTY,
diff --git a/src/main/java/org/openrewrite/staticanalysis/JavaElementFactory.java b/src/main/java/org/openrewrite/staticanalysis/JavaElementFactory.java
@@ -144,12 +144,12 @@ static J.MemberReference newInstanceMethodReference(Expression containing, Strin
     private static JavaType.@Nullable Class getClassType(@Nullable JavaType type) {
         if (type instanceof JavaType.Class) {
             JavaType.Class classType = (JavaType.Class) type;
-            if (classType.getFullyQualifiedName().equals("java.lang.Class")) {
+            if ("java.lang.Class".equals(classType.getFullyQualifiedName())) {
                 return classType;
             }
-            if (classType.getFullyQualifiedName().equals("java.lang.Object")) {
+            if ("java.lang.Object".equals(classType.getFullyQualifiedName())) {
                 for (JavaType.Method method : classType.getMethods()) {
-                    if (method.getName().equals("getClass")) {
+                    if ("getClass".equals(method.getName())) {
                         return getClassType(method.getReturnType());
                     }
                 }
diff --git a/src/main/java/org/openrewrite/staticanalysis/MinimumSwitchCases.java b/src/main/java/org/openrewrite/staticanalysis/MinimumSwitchCases.java
@@ -242,7 +242,7 @@ private List<Statement> getStatements(J.Case aCase) {
             }
 
             private boolean isDefault(J.Case case_) {
-                return case_.getPattern() instanceof J.Identifier && ((J.Identifier) case_.getPattern()).getSimpleName().equals("default");
+                return case_.getPattern() instanceof J.Identifier && "default".equals(((J.Identifier) case_.getPattern()).getSimpleName());
             }
 
             private boolean switchesOnEnum(J.Switch switch_) {
diff --git a/src/main/java/org/openrewrite/staticanalysis/ReplaceClassIsInstanceWithInstanceof.java b/src/main/java/org/openrewrite/staticanalysis/ReplaceClassIsInstanceWithInstanceof.java
@@ -95,7 +95,7 @@ private J mapInstanceOf(J tree, Function<J.InstanceOf, J.InstanceOf> fun) {
             private boolean isObjectClass(@Nullable Expression expression) {
                 if (expression instanceof J.FieldAccess) {
                     J.FieldAccess fieldAccess = (J.FieldAccess) expression;
-                    if (fieldAccess.getName().getSimpleName().equals("class") && fieldAccess.getTarget() instanceof Identifier) {
+                    if ("class".equals(fieldAccess.getName().getSimpleName()) && fieldAccess.getTarget() instanceof Identifier) {
                         Identifier identifier = (Identifier) fieldAccess.getTarget();
                         return identifier.getType() instanceof JavaType.Class;
                     }
diff --git a/src/main/java/org/openrewrite/staticanalysis/ReplaceLambdaWithMethodReference.java b/src/main/java/org/openrewrite/staticanalysis/ReplaceLambdaWithMethodReference.java
@@ -100,7 +100,7 @@ public J visitLambda(J.Lambda lambda, ExecutionContext ctx) {
                     if (classLiteral != null) {
                         //noinspection DataFlowIssue
                         JavaType.FullyQualified rawClassType = ((JavaType.Parameterized) classLiteral.getType()).getType();
-                        Optional<JavaType.Method> isInstanceMethod = rawClassType.getMethods().stream().filter(m -> m.getName().equals("isInstance")).findFirst();
+                        Optional<JavaType.Method> isInstanceMethod = rawClassType.getMethods().stream().filter(m -> "isInstance".equals(m.getName())).findFirst();
                         if (isInstanceMethod.isPresent()) {
                             J.MemberReference updated = newInstanceMethodReference(classLiteral, isInstanceMethod.get(), lambda.getType()).withPrefix(lambda.getPrefix());
                             doAfterVisit(service(ImportService.class).shortenFullyQualifiedTypeReferencesIn(updated));
@@ -123,7 +123,7 @@ public J visitLambda(J.Lambda lambda, ExecutionContext ctx) {
                         if (classLiteral != null) {
                             //noinspection DataFlowIssue
                             JavaType.FullyQualified classType = ((JavaType.Parameterized) classLiteral.getType()).getType();
-                            Optional<JavaType.Method> castMethod = classType.getMethods().stream().filter(m -> m.getName().equals("cast")).findFirst();
+                            Optional<JavaType.Method> castMethod = classType.getMethods().stream().filter(m -> "cast".equals(m.getName())).findFirst();
                             if (castMethod.isPresent()) {
                                 J.MemberReference updated = newInstanceMethodReference(classLiteral, castMethod.get(), lambda.getType()).withPrefix(lambda.getPrefix());
                                 doAfterVisit(service(ImportService.class).shortenFullyQualifiedTypeReferencesIn(updated));
@@ -323,7 +323,7 @@ private boolean isNullCheck(J j1, J j2) {
         private boolean isMethodReferenceAmbiguous(JavaType.Method method) {
             int count = 0;
             for (JavaType.Method meth : method.getDeclaringType().getMethods()) {
-                if (meth.getName().equals(method.getName()) && !meth.getName().equals("println") && !meth.isConstructor()) {
+                if (meth.getName().equals(method.getName()) && !"println".equals(meth.getName()) && !meth.isConstructor()) {
                     if (++count > 1) {
                         return true;
                     }
diff --git a/src/main/java/org/openrewrite/staticanalysis/TernaryOperatorsShouldNotBeNested.java b/src/main/java/org/openrewrite/staticanalysis/TernaryOperatorsShouldNotBeNested.java
@@ -279,7 +279,7 @@ private Optional<J.Identifier> findConditionIdentifier(final J.Ternary ternary)
             J.Identifier result = null;
             if (ternary.getCondition() instanceof J.MethodInvocation) {
                 J.MethodInvocation inv = (J.MethodInvocation) ternary.getCondition();
-                if (!inv.getSimpleName().equals("equals")) {
+                if (!"equals".equals(inv.getSimpleName())) {
                     return Optional.empty();
                 }
                 if (inv.getArguments().size() == 1) {
diff --git a/src/main/java/org/openrewrite/staticanalysis/UnnecessaryExplicitTypeArguments.java b/src/main/java/org/openrewrite/staticanalysis/UnnecessaryExplicitTypeArguments.java
@@ -86,7 +86,7 @@ public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, Execu
                     }
                     inferredType = ((NameTree) enclosing).getType();
                 } else if (enclosing instanceof J.Return) {
-                    Object e = getCursor().dropParentUntil(p -> p instanceof J.MethodDeclaration || p instanceof J.Lambda || p.equals(Cursor.ROOT_VALUE)).getValue();
+                    Object e = getCursor().dropParentUntil(p -> p instanceof J.MethodDeclaration || p instanceof J.Lambda || Cursor.ROOT_VALUE.equals(p)).getValue();
                     if (e instanceof J.MethodDeclaration) {
                         J.MethodDeclaration methodDeclaration = (J.MethodDeclaration) e;
                         if (methodDeclaration.getReturnTypeExpression() != null) {
diff --git a/src/main/java/org/openrewrite/staticanalysis/UseLambdaForFunctionalInterface.java b/src/main/java/org/openrewrite/staticanalysis/UseLambdaForFunctionalInterface.java
@@ -258,7 +258,7 @@ private static boolean usesThis(Cursor cursor) {
         new JavaVisitor<Integer>() {
             @Override
             public J visitIdentifier(J.Identifier ident, Integer integer) {
-                if (ident.getSimpleName().equals("this")) {
+                if ("this".equals(ident.getSimpleName())) {
                     hasThis.set(true);
                 }
                 return super.visitIdentifier(ident, integer);

Original file line number	Diff line number	Diff line change
`@@ -94,7 +94,7 @@ public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, Execu`
`94`	`94`	`appendToString = true;`
`95`	`95`	`} else if ((exp instanceof J.Identifier \|\| exp instanceof J.MethodInvocation) && exp.getType() != null) {`
`96`	`96`	`JavaType.FullyQualified fullyQualified = TypeUtils.asFullyQualified(exp.getType());`
`97`		`- if (fullyQualified != null && fullyQualified.getFullyQualifiedName().equals("java.lang.String")) {`
	`97`	`+ if (fullyQualified != null && "java.lang.String".equals(fullyQualified.getFullyQualifiedName())) {`
`98`	`98`	`addToGroups(group, groups);`
`99`	`99`	`appendToString = true;`
`100`	`100`	`}`
Original file line number	Diff line number	Diff line change
`@@ -214,7 +214,7 @@ private boolean isDefaultCaseLastOrNotPresent(J.Switch switch_) {`
`214`	`214`
`215`	`215`	`private boolean isDefaultCase(J.Case case_) {`
`216`	`216`	`J elem = case_.getCaseLabels().get(0);`
`217`		`- return elem instanceof J.Identifier && ((J.Identifier) elem).getSimpleName().equals("default");`
	`217`	`+ return elem instanceof J.Identifier && "default".equals(((J.Identifier) elem).getSimpleName());`
`218`	`218`	`}`
`219`	`219`
`220`	`220`	`}`
Original file line number	Diff line number	Diff line change
`@@ -144,12 +144,12 @@ static J.MemberReference newInstanceMethodReference(Expression containing, Strin`
`144`	`144`	`private static JavaType.@Nullable Class getClassType(@Nullable JavaType type) {`
`145`	`145`	`if (type instanceof JavaType.Class) {`
`146`	`146`	`JavaType.Class classType = (JavaType.Class) type;`
`147`		`- if (classType.getFullyQualifiedName().equals("java.lang.Class")) {`
	`147`	`+ if ("java.lang.Class".equals(classType.getFullyQualifiedName())) {`
`148`	`148`	`return classType;`
`149`	`149`	`}`
`150`		`- if (classType.getFullyQualifiedName().equals("java.lang.Object")) {`
	`150`	`+ if ("java.lang.Object".equals(classType.getFullyQualifiedName())) {`
`151`	`151`	`for (JavaType.Method method : classType.getMethods()) {`
`152`		`- if (method.getName().equals("getClass")) {`
	`152`	`+ if ("getClass".equals(method.getName())) {`
`153`	`153`	`return getClassType(method.getReturnType());`
`154`	`154`	`}`
`155`	`155`	`}`
Original file line number	Diff line number	Diff line change
`@@ -242,7 +242,7 @@ private List<Statement> getStatements(J.Case aCase) {`
`242`	`242`	`}`
`243`	`243`
`244`	`244`	`private boolean isDefault(J.Case case_) {`
`245`		`- return case_.getPattern() instanceof J.Identifier && ((J.Identifier) case_.getPattern()).getSimpleName().equals("default");`
	`245`	`+ return case_.getPattern() instanceof J.Identifier && "default".equals(((J.Identifier) case_.getPattern()).getSimpleName());`
`246`	`246`	`}`
`247`	`247`
`248`	`248`	`private boolean switchesOnEnum(J.Switch switch_) {`
Original file line number	Diff line number	Diff line change
`@@ -95,7 +95,7 @@ private J mapInstanceOf(J tree, Function<J.InstanceOf, J.InstanceOf> fun) {`
`95`	`95`	`private boolean isObjectClass(@Nullable Expression expression) {`
`96`	`96`	`if (expression instanceof J.FieldAccess) {`
`97`	`97`	`J.FieldAccess fieldAccess = (J.FieldAccess) expression;`
`98`		`- if (fieldAccess.getName().getSimpleName().equals("class") && fieldAccess.getTarget() instanceof Identifier) {`
	`98`	`+ if ("class".equals(fieldAccess.getName().getSimpleName()) && fieldAccess.getTarget() instanceof Identifier) {`
`99`	`99`	`Identifier identifier = (Identifier) fieldAccess.getTarget();`
`100`	`100`	`return identifier.getType() instanceof JavaType.Class;`
`101`	`101`	`}`
Original file line number	Diff line number	Diff line change
`@@ -279,7 +279,7 @@ private Optional<J.Identifier> findConditionIdentifier(final J.Ternary ternary)`
`279`	`279`	`J.Identifier result = null;`
`280`	`280`	`if (ternary.getCondition() instanceof J.MethodInvocation) {`
`281`	`281`	`J.MethodInvocation inv = (J.MethodInvocation) ternary.getCondition();`
`282`		`- if (!inv.getSimpleName().equals("equals")) {`
	`282`	`+ if (!"equals".equals(inv.getSimpleName())) {`
`283`	`283`	`return Optional.empty();`
`284`	`284`	`}`
`285`	`285`	`if (inv.getArguments().size() == 1) {`
Original file line number	Diff line number	Diff line change
`@@ -86,7 +86,7 @@ public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, Execu`
`86`	`86`	`}`
`87`	`87`	`inferredType = ((NameTree) enclosing).getType();`
`88`	`88`	`} else if (enclosing instanceof J.Return) {`
`89`		`- Object e = getCursor().dropParentUntil(p -> p instanceof J.MethodDeclaration \|\| p instanceof J.Lambda \|\| p.equals(Cursor.ROOT_VALUE)).getValue();`
	`89`	`+ Object e = getCursor().dropParentUntil(p -> p instanceof J.MethodDeclaration \|\| p instanceof J.Lambda \|\| Cursor.ROOT_VALUE.equals(p)).getValue();`
`90`	`90`	`if (e instanceof J.MethodDeclaration) {`
`91`	`91`	`J.MethodDeclaration methodDeclaration = (J.MethodDeclaration) e;`
`92`	`92`	`if (methodDeclaration.getReturnTypeExpression() != null) {`
Original file line number	Diff line number	Diff line change
`@@ -258,7 +258,7 @@ private static boolean usesThis(Cursor cursor) {`
`258`	`258`	`new JavaVisitor<Integer>() {`
`259`	`259`	`@Override`
`260`	`260`	`public J visitIdentifier(J.Identifier ident, Integer integer) {`
`261`		`- if (ident.getSimpleName().equals("this")) {`
	`261`	`+ if ("this".equals(ident.getSimpleName())) {`
`262`	`262`	`hasThis.set(true);`
`263`	`263`	`}`
`264`	`264`	`return super.visitIdentifier(ident, integer);`