KT-5287 J2K: Convert class with private constructor and static functions to "object" instead of class with "class object"

#KT-5287 Fixed

j2k/src/org/jetbrains/kotlin/j2k/ClassBodyConverter.kt

@@ -49,14 +49,15 @@ enum class AccessorKind {
 
 class ClassBodyConverter(private val psiClass: PsiClass,
                          private val converter: Converter,
-                         private val isOpenClass: Boolean) {
+                         private val isOpenClass: Boolean,
+                         private val isObject: Boolean) {
     private val membersToRemove = HashSet<PsiMember>()
     private val fieldCorrections = HashMap<PsiField, FieldCorrectionInfo>()
 
     public fun convertBody(): ClassBody {
         processAccessorsToDrop()
 
-        val constructorConverter = if (psiClass.getName() != null)
+        val constructorConverter = if (psiClass.getName() != null && !isObject)
             ConstructorConverter(psiClass, converter, fieldCorrections)
         else
             null
@@ -65,9 +66,10 @@ class ClassBodyConverter(private val psiClass: PsiClass,
         for (element in psiClass.getChildren()) {
             if (element is PsiMember) {
                 if (element is PsiAnnotationMethod) continue // converted in convertAnnotationType()
+                if (isObject && element.isConstructor()) continue // no constructor in object
 
                 val converted = converter.convertMember(element, membersToRemove, constructorConverter)
-                if (converted != null/* && !converted.isEmpty()*/) {
+                if (converted != null) {
                     convertedMembers.put(element, converted)
                 }
             }
@@ -77,6 +79,13 @@ class ClassBodyConverter(private val psiClass: PsiClass,
             convertedMembers.remove(member)
         }
 
+        val lBrace = LBrace().assignPrototype(psiClass.getLBrace())
+        val rBrace = RBrace().assignPrototype(psiClass.getRBrace())
+
+        if (isObject) {
+            return ClassBody(null, emptyList(), convertedMembers.values().toList(), emptyList(), lBrace, rBrace)
+        }
+
         val useCompanionObject = shouldGenerateCompanionObject(convertedMembers)
 
         val members = ArrayList<Member>()
@@ -105,9 +114,6 @@ class ClassBodyConverter(private val psiClass: PsiClass,
             primaryConstructorSignature = null // no "()" after class name is needed in this case
         }
 
-        val lBrace = LBrace().assignPrototype(psiClass.getLBrace())
-        val rBrace = RBrace().assignPrototype(psiClass.getRBrace())
-
         return ClassBody(primaryConstructorSignature, constructorConverter?.baseClassParams ?: listOf(), members, companionObjectMembers, lBrace, rBrace)
     }
 

j2k/src/org/jetbrains/kotlin/j2k/CodeConverter.kt

@@ -153,7 +153,7 @@ class CodeConverter(
     }
 
     public fun convertAnonymousClassBody(anonymousClass: PsiAnonymousClass): AnonymousClassBody {
-        return AnonymousClassBody(ClassBodyConverter(anonymousClass, converter, false).convertBody(),
+        return AnonymousClassBody(ClassBodyConverter(anonymousClass, converter, isOpenClass = false, isObject = false).convertBody(),
                                   anonymousClass.getBaseClassType().resolve()?.isInterface() ?: false).assignPrototype(anonymousClass)
     }
 

j2k/src/org/jetbrains/kotlin/j2k/Converter.kt

@@ -16,20 +16,21 @@
 
 package org.jetbrains.kotlin.j2k
 
+import com.intellij.openapi.project.Project
 import com.intellij.psi.*
+import com.intellij.psi.CommonClassNames.*
+import com.intellij.psi.util.PsiMethodUtil
+import com.intellij.psi.util.PsiTreeUtil
 import org.jetbrains.kotlin.j2k.ast.*
 import org.jetbrains.kotlin.j2k.ast.Annotation
 import org.jetbrains.kotlin.j2k.ast.Class
 import org.jetbrains.kotlin.j2k.ast.Enum
-import java.util.*
+import org.jetbrains.kotlin.j2k.ast.Object
-import com.intellij.psi.CommonClassNames.*
-import org.jetbrains.kotlin.types.expressions.OperatorConventions.*
-import com.intellij.openapi.project.Project
-import com.intellij.psi.util.PsiMethodUtil
-import com.intellij.psi.util.PsiTreeUtil
-import org.jetbrains.kotlin.j2k.usageProcessing.UsageProcessing
 import org.jetbrains.kotlin.j2k.usageProcessing.FieldToPropertyProcessing
+import org.jetbrains.kotlin.j2k.usageProcessing.UsageProcessing
 import org.jetbrains.kotlin.j2k.usageProcessing.UsageProcessingExpressionConverter
+import org.jetbrains.kotlin.types.expressions.OperatorConventions.*
+import java.util.ArrayList
 
 class Converter private(
         private val elementToConvert: PsiElement,
@@ -150,42 +151,71 @@ class Converter private(
         val annotations = convertAnnotations(psiClass)
         var modifiers = convertModifiers(psiClass)
         val typeParameters = convertTypeParameterList(psiClass.getTypeParameterList())
-        val implementsTypes = convertToNotNullableTypes(psiClass.getImplementsListTypes())
         val extendsTypes = convertToNotNullableTypes(psiClass.getExtendsListTypes())
+        val implementsTypes = convertToNotNullableTypes(psiClass.getImplementsListTypes())
         val name = psiClass.declarationIdentifier()
 
         return when {
             psiClass.isInterface() -> {
-                var classBody = ClassBodyConverter(psiClass, this, false).convertBody()
+                val classBody = ClassBodyConverter(psiClass, this, isOpenClass = false, isObject = false).convertBody()
                 Trait(name, annotations, modifiers, typeParameters, extendsTypes, listOf(), implementsTypes, classBody)
             }
 
             psiClass.isEnum() -> {
-                var classBody = ClassBodyConverter(psiClass, this, false).convertBody()
+                val classBody = ClassBodyConverter(psiClass, this, isOpenClass = false, isObject = false).convertBody()
                 Enum(name, annotations, modifiers, typeParameters, listOf(), listOf(), implementsTypes, classBody)
             }
 
             else -> {
-                if (needOpenModifier(psiClass)) {
+                if (shouldConvertIntoObject(psiClass)) {
-                    modifiers = modifiers.with(Modifier.OPEN)
+                    val classBody = ClassBodyConverter(psiClass, this, isOpenClass = false, isObject = true).convertBody()
+                    Object(name, annotations, modifiers.without(Modifier.ABSTRACT), classBody)
                 }
-
+                else {
                     if (psiClass.getContainingClass() != null && !psiClass.hasModifierProperty(PsiModifier.STATIC)) {
                         modifiers = modifiers.with(Modifier.INNER)
                     }
 
-                var classBody = ClassBodyConverter(psiClass, this, modifiers.contains(Modifier.OPEN)).convertBody()
+                    val openModifier = if (psiClass.hasModifierProperty(PsiModifier.FINAL) || psiClass.hasModifierProperty(PsiModifier.ABSTRACT))
+                        false
+                    else
+                        settings.openByDefault || referenceSearcher.hasInheritors(psiClass)
 
+                    if (openModifier) {
+                        modifiers = modifiers.with(Modifier.OPEN)
+                    }
+
+                    val classBody = ClassBodyConverter(psiClass, this, modifiers.contains(Modifier.OPEN) || modifiers.contains(Modifier.ABSTRACT), isObject = false).convertBody()
                     Class(name, annotations, modifiers, typeParameters, extendsTypes, classBody.baseClassParams, implementsTypes, classBody)
                 }
+            }
         }.assignPrototype(psiClass)
     }
 
-    private fun needOpenModifier(psiClass: PsiClass): Boolean {
+    private fun shouldConvertIntoObject(psiClass: PsiClass): Boolean {
-        return if (settings.openByDefault)
+        val methods = psiClass.getMethods()
-            !psiClass.hasModifierProperty(PsiModifier.FINAL) && !psiClass.hasModifierProperty(PsiModifier.ABSTRACT)
+        val fields = psiClass.getFields()
-        else
+        val classes = psiClass.getInnerClasses()
-            referenceSearcher.hasInheritors(psiClass)
+        if (methods.isEmpty() && fields.isEmpty()) return false
+        fun isStatic(member: PsiMember) = member.hasModifierProperty(PsiModifier.STATIC)
+        if (!methods.all { isStatic(it) || it.isConstructor() } || !fields.all(::isStatic) || !classes.all(::isStatic)) return false
+
+        val constructors = psiClass.getConstructors()
+        if (constructors.size() > 1) return false
+        val constructor = constructors.singleOrNull()
+        if (constructor != null) {
+            if (!constructor.hasModifierProperty(PsiModifier.PRIVATE)) return false
+            if (constructor.getParameterList().getParameters().isNotEmpty()) return false
+            if (constructor.getBody()?.getStatements()?.isNotEmpty() ?: false) return false
+            if (constructor.getModifierList().getAnnotations().isNotEmpty()) return false
+        }
+
+        if (psiClass.getExtendsListTypes().isNotEmpty() || psiClass.getImplementsListTypes().isNotEmpty()) return false
+        if (psiClass.getTypeParameters().isNotEmpty()) return false
+
+        if (referenceSearcher.hasInheritors(psiClass)) return false
+
+        return true
     }
 
     private fun convertAnnotationType(psiClass: PsiClass): Class {
@@ -215,7 +245,7 @@ class Converter private(
             null
 
         // to convert fields and nested types - they are not allowed in Kotlin but we convert them and let user refactor code
-        var classBody = ClassBodyConverter(psiClass, this, false).convertBody()
+        var classBody = ClassBodyConverter(psiClass, this, isOpenClass = false, isObject = false).convertBody()
         classBody = ClassBody(constructorSignature, classBody.baseClassParams, classBody.members, classBody.companionObjectMembers, classBody.lBrace, classBody.rBrace)
 
         val annotationAnnotation = Annotation(Identifier("annotation").assignNoPrototype(), listOf(), false, false).assignNoPrototype()

j2k/src/org/jetbrains/kotlin/j2k/ast/Class.kt

@@ -16,7 +16,8 @@
 
 package org.jetbrains.kotlin.j2k.ast
 
-import org.jetbrains.kotlin.j2k.*
+import org.jetbrains.kotlin.j2k.CodeBuilder
+import org.jetbrains.kotlin.j2k.append
 
 open class Class(
         val name: Identifier,
@@ -68,3 +69,14 @@ open class Class(
     protected open fun presentationModifiers(): Modifiers
             = if (modifiers.contains(Modifier.ABSTRACT)) modifiers.without(Modifier.OPEN) else modifiers
 }
+
+class Object(
+        name: Identifier,
+        annotations: Annotations,
+        modifiers: Modifiers,
+        body: ClassBody
+) : Class(name, annotations, modifiers, TypeParameterList.Empty, emptyList(), emptyList(), emptyList(), body) {
+
+    override val keyword: String
+        get() = "object"
+}

j2k/testData/fileOrElement/anonymousBlock/oneStaticAnonBlock.kt

@@ -1,9 +1,7 @@
-class Test {
+object Test {
-    companion object {
     var str: String
 
     init {
         str = "Ola"
     }
-    }
 }

j2k/testData/fileOrElement/callChainExpression/libraryFieldCall.kt

@@ -1,8 +1,6 @@
 // ERROR: Property must be initialized or be abstract
-class Library {
+object Library {
-    companion object {
     val ourOut: java.io.PrintStream
-    }
 }
 
 class User {

j2k/testData/fileOrElement/callChainExpression/libraryMethodCall.kt

@@ -1,12 +1,10 @@
-class Library {
+object Library {
-    companion object {
     fun call() {
     }
 
     fun getString(): String {
         return ""
     }
-    }
 }
 
 class User {

j2k/testData/fileOrElement/class/ClassShadowing.java

@@ -1,7 +1,10 @@
 package test;
 
+import java.lang.String;
+
 public class Short {
-	public static Short valueOf(String value) {return new Short();}
+        public Short(String s){}
+	public static Short valueOf(String value) {return new Short(value);}
 }
 
 class Test {

j2k/testData/fileOrElement/class/ClassShadowing.kt

@@ -1,19 +1,17 @@
 package test
 
-public class Short {
+public class Short(s: String) {
     companion object {
         public fun valueOf(value: String): Short {
-            return Short()
+            return Short(value)
         }
     }
 }
 
-class Test {
+object Test {
-    companion object {
     public fun test() {
         test.Short.valueOf("1")
         test.Short.valueOf("1")
         java.lang.Short.valueOf("1")
     }
-    }
 }

j2k/testData/fileOrElement/class/notUtilityClass.java

@@ -0,0 +1,7 @@
+class Base {
+    public static final int CONSTANT = 10;
+}
+
+class Derived extends Base {
+    void foo(){}
+}

j2k/testData/fileOrElement/class/notUtilityClass.kt

@@ -0,0 +1,10 @@
+open class Base {
+    companion object {
+        public val CONSTANT: Int = 10
+    }
+}
+
+class Derived : Base() {
+    fun foo() {
+    }
+}

j2k/testData/fileOrElement/class/oneStaticMethod.kt

@@ -1,7 +1,5 @@
-class S {
+object S {
-    companion object {
     fun staticF(): Boolean {
         return true
     }
-    }
 }

j2k/testData/fileOrElement/class/twoStaticMethod.kt

@@ -1,5 +1,4 @@
-class S {
+object S {
-    companion object {
     fun sB(): Boolean {
         return true
     }
@@ -7,5 +6,4 @@ class S {
     fun sI(): Int {
         return 1
     }
-    }
 }

j2k/testData/fileOrElement/class/utilityClass1.java

@@ -0,0 +1,6 @@
+class Util {
+    public static void util1() {}
+    public static void util2() {}
+
+    public static final int CONSTANT = 10;
+}

j2k/testData/fileOrElement/class/utilityClass1.kt

@@ -0,0 +1,9 @@
+object Util {
+    public fun util1() {
+    }
+
+    public fun util2() {
+    }
+
+    public val CONSTANT: Int = 10
+}

j2k/testData/fileOrElement/class/utilityClass2.java

@@ -0,0 +1,8 @@
+class Util {
+    private Util(){}
+
+    public static void util1() {}
+    public static void util2() {}
+
+    public static final int CONSTANT = 10;
+}

j2k/testData/fileOrElement/class/utilityClass2.kt

@@ -0,0 +1,10 @@
+object Util {
+
+    public fun util1() {
+    }
+
+    public fun util2() {
+    }
+
+    public val CONSTANT: Int = 10
+}

j2k/testData/fileOrElement/class/utilityClass3.java

@@ -0,0 +1,6 @@
+abstract class Util {
+    public static void util1() {}
+    public static void util2() {}
+
+    public static final int CONSTANT = 10;
+}

j2k/testData/fileOrElement/class/utilityClass3.kt

@@ -0,0 +1,9 @@
+object Util {
+    public fun util1() {
+    }
+
+    public fun util2() {
+    }
+
+    public val CONSTANT: Int = 10
+}

j2k/testData/fileOrElement/classExpression/primitivesAndArrays.kt

@@ -1,5 +1,4 @@
-public class A {
+public object A {
-    companion object {
     public fun main(args: Array<String>) {
         System.out.println(Void.TYPE)
         System.out.println(Integer.TYPE)
@@ -8,7 +7,6 @@ public class A {
         System.out.println(javaClass<Array<Any>>())
         System.out.println(javaClass<Array<Array<Any>>>())
     }
-    }
 }
 
 fun main(args: Array<String>) = A.main(args)

j2k/testData/fileOrElement/constructors/allCallsPrimary.kt

@@ -2,12 +2,10 @@ package pack
 
 class C(arg1: Int, arg2: Int = 0, arg3: Int = 0)
 
-public class User {
+public object User {
-    companion object {
     public fun main() {
         val c1 = C(100, 100, 100)
         val c2 = C(100, 100)
         val c3 = C(100)
     }
-    }
 }

j2k/testData/fileOrElement/constructors/allCallsPrimary2.kt

@@ -18,12 +18,10 @@ class C(val myArg1: Int) {
     }
 }
 
-public class User {
+public object User {
-    companion object {
     public fun main() {
         val c1 = C(100, 100, 100)
         val c2 = C(100, 100)
         val c3 = C(100)
     }
-    }
 }

j2k/testData/fileOrElement/constructors/chain.kt

@@ -9,12 +9,10 @@ class C(arg1: Int, arg2: Int, arg3: Int) {
     }
 }
 
-public class User {
+public object User {
-    companion object {
     public fun main() {
         val c1 = C(1, 2, 3)
         val c2 = C(5, 6)
         val c3 = C(7)
     }
-    }
 }

j2k/testData/fileOrElement/constructors/customerBuilder.kt

@@ -33,12 +33,10 @@ class CustomerBuilder {
     }
 }
 
-public class User {
+public object User {
-    companion object {
     public fun main() {
         val customer = CustomerBuilder().WithFirstName("Homer").WithLastName("Simpson").Build()
         System.out.println(customer.firstName)
         System.out.println(customer.lastName)
     }
-    }
 }

j2k/testData/fileOrElement/constructors/genericIdentifier.kt

@@ -20,12 +20,10 @@ public class Identifier<T> {
     }
 }
 
-public class User {
+public object User {
-    companion object {
     public fun main() {
         val i1 = Identifier("name", false, true)
         val i2 = Identifier("name", false)
         val i3 = Identifier("name")
     }
-    }
 }

j2k/testData/fileOrElement/constructors/identifier.kt

@@ -20,12 +20,10 @@ public class Identifier {
     }
 }
 
-public class User {
+public object User {
-    companion object {
     public fun main() {
         val i1 = Identifier("name", false, true)
         val i2 = Identifier("name", false)
         val i3 = Identifier("name")
     }
-    }
 }

j2k/testData/fileOrElement/constructors/noPrimary.kt

@@ -11,12 +11,10 @@ class C {
     }
 }
 
-public class User {
+public object User {
-    companion object {
     public fun main() {
         val c1 = C(1, 2, 3)
         val c2 = C(5, 6)
         val c3 = C(7)
     }
-    }
 }

j2k/testData/fileOrElement/constructors/parameterModification.kt

@@ -17,12 +17,10 @@ class C(arg1: Int, arg2: Int = 0, arg3: Int = 0) {
     }
 }
 
-public class User {
+public object User {
-    companion object {
     public fun main() {
         val c1 = C(100, 100, 100)
         val c2 = C(100, 100)
         val c3 = C(100)
     }
-    }
 }

j2k/testData/fileOrElement/constructors/secondaryConstructorsInNestedClass.kt

@@ -1,4 +1,4 @@
-class Outer {
+object Outer {
     private class Nested1() {
 
         public constructor(a: Int) : this() {
@@ -48,13 +48,10 @@ class Outer {
         }
     }
 
-    companion object {
-
     fun foo() {
         val nested1 = Nested1(1)
         val nested2 = Nested2(2)
         val nested3 = Nested3(3)
         val nested4 = Nested4(4)
     }
-    }
 }

j2k/testData/fileOrElement/constructors/withManyDefaultParams.kt

@@ -24,10 +24,8 @@ public class Test {
     }
 }
 
-public class User {
+public object User {
-    companion object {
     public fun main() {
         val t = Test("name")
     }
-    }
 }

j2k/testData/fileOrElement/for/withContinue1.kt

@@ -1,5 +1,4 @@
-public class TestClass {
+public object TestClass {
-    companion object {
     public fun main(args: Array<String>) {
         var i = 0
         while (i < 10) {
@@ -12,7 +11,6 @@ public class TestClass {
             ++i
         }
     }
-    }
 }
 
 fun main(args: Array<String>) = TestClass.main(args)

j2k/testData/fileOrElement/for/withContinue2.kt

@@ -1,5 +1,4 @@
-public class TestClass {
+public object TestClass {
-    companion object {
     public fun main(args: Array<String>) {
         var i = 0
         var j = 1
@@ -15,7 +14,6 @@ public class TestClass {
             j *= 2
         }
     }
-    }
 }
 
 fun main(args: Array<String>) = TestClass.main(args)

j2k/testData/fileOrElement/for/withContinue3.kt

@@ -1,5 +1,4 @@
-public class TestClass {
+public object TestClass {
-    companion object {
     public fun main(args: Array<String>) {
         var i = 1
         while (i < 1000) {
@@ -11,7 +10,6 @@ public class TestClass {
             i *= 2
         }
     }
-    }
 }
 
 fun main(args: Array<String>) = TestClass.main(args)

j2k/testData/fileOrElement/for/withContinueAndLabels.kt

@@ -1,6 +1,5 @@
 // ERROR: The label '@OuterLoop1' does not denote a loop
-public class TestClass {
+public object TestClass {
-    companion object {
     public fun main(args: Array<String>) {
         var i = 1
         @OuterLoop1 @OuterLoop2 while (i < 1000) {
@@ -24,7 +23,6 @@ public class TestClass {
             i *= 2
         }
     }
-    }
 }
 
 fun main(args: Array<String>) = TestClass.main(args)

j2k/testData/fileOrElement/formatting/staticMembersWithComments.kt

@@ -1,5 +1,4 @@
-class F {
+object F {
-    companion object {
 
     //c1
 
@@ -23,7 +22,6 @@ class F {
 
     fun f3() {
     }
-    }
 
     //c5
 }

j2k/testData/fileOrElement/function/main.kt

@@ -1,4 +1,2 @@
-companion object {
+public fun main(args: Array<String>) {
-    public fun main(args: Array<String>) {
-    }
 }

j2k/testData/fileOrElement/function/main2.kt

@@ -1,8 +1,6 @@
-public class A {
+public object A {
-    companion object {
     public fun main(args: Array<String>) {
     }
-    }
 }
 
 fun main(args: Array<String>) = A.main(args)

j2k/testData/fileOrElement/function/mainAndNullabilitySetting.kt

@@ -1,9 +1,7 @@
 // !forceNotNullTypes: false
-public class A {
+public object A {
-    companion object {
     public fun main(args: Array<String>) {
     }
-    }
 }
 
 fun main(args: Array<String>) = A.main(args)

j2k/testData/fileOrElement/issues/arrayLength.kt

@@ -1,7 +1,5 @@
-class Test {
+object Test {
-    companion object {
     public fun foo(args: Array<String>): Int {
         return args.size()
     }
-    }
 }

j2k/testData/fileOrElement/issues/doNotQualifyStatic.kt

@@ -1,12 +1,9 @@
-class Outer {
+object Outer {
+    public var o: Any? = Object()
 
     public class Nested {
         public fun foo() {
             o = null
         }
     }
-
-    companion object {
-        public var o: Any? = Object()
-    }
 }

j2k/testData/fileOrElement/issues/kt-1074.kt

@@ -1,7 +1,6 @@
 package demo
 
-class Test {
+object Test {
-    companion object {
     fun subListRangeCheck(fromIndex: Int, toIndex: Int, size: Int) {
         if (fromIndex < 0)
             throw IndexOutOfBoundsException("fromIndex = " + fromIndex)
@@ -10,5 +9,4 @@ class Test {
         if (fromIndex > toIndex)
             throw IllegalArgumentException("fromIndex(" + fromIndex + ") > toIndex(" + toIndex + ")")
     }
-    }
 }

j2k/testData/fileOrElement/issues/kt-638.kt

@@ -20,14 +20,12 @@ public class Identifier<T> {
     }
 }
 
-public class User {
+public object User {
-    companion object {
     public fun main(args: Array<String>) {
         val i1 = Identifier("name", false, true)
         val i2 = Identifier("name", false)
         val i3 = Identifier("name")
     }
-    }
 }
 
 fun main(args: Array<String>) = User.main(args)

j2k/testData/fileOrElement/issues/kt-807.kt

@@ -4,8 +4,7 @@
 // ERROR: Unresolved reference: close
 import java.io.*
 
-class FileRead {
+object FileRead {
-    companion object {
     public fun main(args: Array<String>) {
         try {
             val fstream = FileInputStream()
@@ -21,7 +20,6 @@ class FileRead {
         }
 
     }
-    }
 }
 
 fun main(args: Array<String>) = FileRead.main(args)

j2k/testData/fileOrElement/issues/kt-809-string.kt

@@ -4,10 +4,8 @@ class Container {
     var myString = "1"
 }
 
-class One {
+object One {
-    companion object {
     var myContainer = Container()
-    }
 }
 
 class StringContainer(s: String)

j2k/testData/fileOrElement/issues/kt-809.kt

@@ -4,10 +4,8 @@ class Container {
     var myInt = 1
 }
 
-class One {
+object One {
-    companion object {
     var myContainer = Container()
-    }
 }
 
 class IntContainer(i: Int)

j2k/testData/fileOrElement/issues/kt-820-field.kt

@@ -4,10 +4,8 @@ class Container {
     var myInt = 1
 }
 
-class One {
+object One {
-    companion object {
     var myContainer = Container()
-    }
 }
 
 class Test {

j2k/testData/fileOrElement/issues/kt-820-string.kt

@@ -1,8 +1,6 @@
-class Test {
+object Test {
-    companion object {
     public fun toFileSystemSafeName(name: String): String {
         val size = name.length()
         return name
     }
-    }
 }

j2k/testData/fileOrElement/issues/kt-820.kt

@@ -4,10 +4,8 @@ class Container {
     var myInt = 1
 }
 
-class One {
+object One {
-    companion object {
     var myContainer = Container()
-    }
 }
 
 class Test {

j2k/testData/fileOrElement/issues/kt-824-isDir.kt

@@ -5,8 +5,7 @@ import java.io.File
 /**
  * User: ignatov
  */
-public class Test {
+public object Test {
-    companion object {
     public fun isDir(parent: File?): Boolean {
         if (parent == null || !parent.exists()) {
             return false
@@ -17,5 +16,4 @@ public class Test {
         } else
             return false
     }
-    }
 }

j2k/testData/fileOrElement/issues/kt-824.kt

@@ -4,10 +4,8 @@ class Container {
     var myBoolean = true
 }
 
-class One {
+object One {
-    companion object {
     var myContainer = Container()
-    }
 }
 
 class Test {

j2k/testData/fileOrElement/issues/kt-871.kt

@@ -1,11 +1,9 @@
 package demo
 
-class Program {
+object Program {
-    companion object {
     public fun main(args: Array<String>) {
         System.out.println("Halo!")
     }
-    }
 }
 
 fun main(args: Array<String>) = Program.main(args)

j2k/testData/fileOrElement/issues/kt-879.kt

@@ -1,5 +1,4 @@
-class Test {
+object Test {
-    companion object {
     public fun getInt(i: Int): Int {
         when (i) {
             0 -> return 0
@@ -9,5 +8,4 @@ class Test {
             else -> return -1
         }
     }
-    }
 }

j2k/testData/fileOrElement/methodCallExpression/vararg1.kt

@@ -1,11 +1,9 @@
 import java.lang.reflect.Constructor
 
-class X {
+object X {
-    companion object {
     throws(javaClass<Exception>())
     fun <T> foo(constructor: Constructor<T>, args1: Array<Any>, args2: Array<Any>) {
         constructor.newInstance(*args1)
         constructor.newInstance(args1, args2)
     }
-    }
 }

j2k/testData/fileOrElement/switch/comlicatedFallDown.kt

@@ -1,7 +1,6 @@
 package demo
 
-public class SwitchDemo {
+public object SwitchDemo {
-    companion object {
     public fun print(o: Any) {
         System.out.println(o)
     }
@@ -81,7 +80,6 @@ public class SwitchDemo {
         for (i in 1..12)
             test(i)
     }
-    }
 }
 
 fun main(args: Array<String>) = SwitchDemo.main(args)

j2k/testData/fileOrElement/switch/emptySwitch.kt

@@ -1,5 +1,4 @@
-public class NonDefault {
+public object NonDefault {
-    companion object {
     public fun main(args: Array<String>) {
 
         val value = 3
@@ -9,7 +8,6 @@ public class NonDefault {
         }
         System.out.println(valueString)
     }
-    }
 }
 
 fun main(args: Array<String>) = NonDefault.main(args)

j2k/testData/fileOrElement/switch/fallDown.kt

@@ -1,7 +1,6 @@
 package switch_demo
 
-public class SwitchDemo {
+public object SwitchDemo {
-    companion object {
     public fun main(args: Array<String>) {
         val month = 8
         val monthString: String
@@ -11,7 +10,6 @@ public class SwitchDemo {
         }
         System.out.println(monthString)
     }
-    }
 }
 
 fun main(args: Array<String>) = SwitchDemo.main(args)

j2k/testData/fileOrElement/switch/fallDownWithBlocks.kt

@@ -1,5 +1,4 @@
-public class C {
+public object C {
-    companion object {
     public fun main(args: Array<String>) {
         when (args.size()) {
             1 -> {
@@ -19,7 +18,6 @@ public class C {
             }
         }
     }
-    }
 }
 
 fun main(args: Array<String>) = C.main(args)

j2k/testData/fileOrElement/switch/kt-539.kt

@@ -1,7 +1,6 @@
 package switch_demo
 
-public class SwitchDemo {
+public object SwitchDemo {
-    companion object {
     public fun main(args: Array<String>) {
 
         val month = 8
@@ -23,7 +22,6 @@ public class SwitchDemo {
         }
         System.out.println(monthString)
     }
-    }
 }
 
 fun main(args: Array<String>) = SwitchDemo.main(args)

j2k/testData/fileOrElement/switch/nondefault.kt

@@ -1,5 +1,4 @@
-public class NonDefault {
+public object NonDefault {
-    companion object {
     public fun main(args: Array<String>) {
 
         val value = 3
@@ -11,7 +10,6 @@ public class NonDefault {
         }
         System.out.println(valueString)
     }
-    }
 }
 
 fun main(args: Array<String>) = NonDefault.main(args)

j2k/testData/fileOrElement/typeParameters/rawTypeCast.kt

@@ -1,11 +1,9 @@
 // ERROR: Type inference failed. Expected type mismatch: found: java.util.HashMap<kotlin.Any!, kotlin.Any!> required: kotlin.Map<kotlin.String, kotlin.String>
 import java.util.*
 
-class A {
+object A {
-    companion object {
     public fun foo(): Map<String, String> {
         val props = Properties()
         return HashMap(props as Map<Any, Any>)
     }
-    }
 }

j2k/tests/org/jetbrains/kotlin/j2k/AbstractJavaToKotlinConverterSingleFileTest.kt

@@ -119,7 +119,7 @@ public abstract class AbstractJavaToKotlinConverterSingleFileTest : AbstractJava
     }
 
     private fun methodToKotlin(text: String, settings: ConverterSettings, project: Project): String {
-        val result = fileToKotlin("final class C {" + text + "}", settings, project).replaceAll("class C \\{", "")
+        val result = fileToKotlin("final class C {" + text + "}", settings, project).replaceAll("class C \\{", "").replaceAll("object C \\{", "")
         return result.substring(0, (result.lastIndexOf("}"))).trim()
     }
 

j2k/tests/org/jetbrains/kotlin/j2k/JavaToKotlinConverterForWebDemoTestGenerated.java

@@ -886,6 +886,12 @@ public class JavaToKotlinConverterForWebDemoTestGenerated extends AbstractJavaTo
             doTest(fileName);
         }
 
+        @TestMetadata("notUtilityClass.java")
+        public void testNotUtilityClass() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/class/notUtilityClass.java");
+            doTest(fileName);
+        }
+
         @TestMetadata("oneStaticFieldOneNonStatic.java")
         public void testOneStaticFieldOneNonStatic() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/class/oneStaticFieldOneNonStatic.java");
@@ -939,6 +945,24 @@ public class JavaToKotlinConverterForWebDemoTestGenerated extends AbstractJavaTo
             String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/class/twoStaticMethod.java");
             doTest(fileName);
         }
+
+        @TestMetadata("utilityClass1.java")
+        public void testUtilityClass1() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/class/utilityClass1.java");
+            doTest(fileName);
+        }
+
+        @TestMetadata("utilityClass2.java")
+        public void testUtilityClass2() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/class/utilityClass2.java");
+            doTest(fileName);
+        }
+
+        @TestMetadata("utilityClass3.java")
+        public void testUtilityClass3() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/class/utilityClass3.java");
+            doTest(fileName);
+        }
     }
 
     @TestMetadata("j2k/testData/fileOrElement/classExpression")

j2k/tests/org/jetbrains/kotlin/j2k/JavaToKotlinConverterSingleFileTestGenerated.java

@@ -886,6 +886,12 @@ public class JavaToKotlinConverterSingleFileTestGenerated extends AbstractJavaTo
             doTest(fileName);
         }
 
+        @TestMetadata("notUtilityClass.java")
+        public void testNotUtilityClass() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/class/notUtilityClass.java");
+            doTest(fileName);
+        }
+
         @TestMetadata("oneStaticFieldOneNonStatic.java")
         public void testOneStaticFieldOneNonStatic() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/class/oneStaticFieldOneNonStatic.java");
@@ -939,6 +945,24 @@ public class JavaToKotlinConverterSingleFileTestGenerated extends AbstractJavaTo
             String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/class/twoStaticMethod.java");
             doTest(fileName);
         }
+
+        @TestMetadata("utilityClass1.java")
+        public void testUtilityClass1() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/class/utilityClass1.java");
+            doTest(fileName);
+        }
+
+        @TestMetadata("utilityClass2.java")
+        public void testUtilityClass2() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/class/utilityClass2.java");
+            doTest(fileName);
+        }
+
+        @TestMetadata("utilityClass3.java")
+        public void testUtilityClass3() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("j2k/testData/fileOrElement/class/utilityClass3.java");
+            doTest(fileName);
+        }
     }
 
     @TestMetadata("j2k/testData/fileOrElement/classExpression")