Fix for KT-9594 J2K: null cast incorrect conversion.

#KT-9594 fixed

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

@@ -109,7 +109,7 @@ class CodeConverter(
 
         val actualType = expression.type ?: return convertedExpression
 
-        if (actualType is PsiPrimitiveType || actualType is PsiClassType && expectedType is PsiPrimitiveType) {
+        if ((actualType is PsiPrimitiveType && actualType != PsiType.NULL) || actualType is PsiClassType && expectedType is PsiPrimitiveType) {
             convertedExpression = BangBangExpression.surroundIfNullable(convertedExpression)
         }
 

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

@@ -270,6 +270,12 @@ class DefaultExpressionConverter : JavaElementVisitor(), ExpressionConverter {
         val value = expression.value
         var text = expression.text!!
         val type = expression.type
+
+        if(expression.isNullLiteral()) {
+            result = LiteralExpression.NullLiteral
+            return
+        }
+
         if (type != null) {
             val typeStr = type.canonicalText
             if (typeStr == "double") {
@@ -314,6 +320,7 @@ class DefaultExpressionConverter : JavaElementVisitor(), ExpressionConverter {
             }
         }
 
+
         result = LiteralExpression(text)
     }
 

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

@@ -84,10 +84,16 @@ class TypeCastExpression(val type: Type, val expression: Expression) : Expressio
         get() = type.isNullable
 }
 
-class LiteralExpression(val literalText: String) : Expression() {
+open class LiteralExpression(val literalText: String) : Expression() {
+
     override fun generateCode(builder: CodeBuilder) {
         builder.append(literalText)
     }
+
+    object NullLiteral : LiteralExpression("null"){
+        override val isNullable: Boolean
+            get() = true
+    }
 }
 
 class ParenthesizedExpression(val expression: Expression) : Expression() {

j2k/testData/fileOrElement/typeCastExpression/castNullObject.java

@@ -0,0 +1,2 @@
+//expression
+(Object) null

j2k/testData/fileOrElement/typeCastExpression/castNullObject.kt

@@ -0,0 +1 @@
+null as Any?

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

@@ -4823,6 +4823,12 @@ public class JavaToKotlinConverterForWebDemoTestGenerated extends AbstractJavaTo
             doTest(fileName);
         }
 
+        @TestMetadata("castNullObject.java")
+        public void testCastNullObject() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/typeCastExpression/castNullObject.java");
+            doTest(fileName);
+        }
+
         @TestMetadata("castNullable.java")
         public void testCastNullable() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/typeCastExpression/castNullable.java");

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

@@ -4823,6 +4823,12 @@ public class JavaToKotlinConverterSingleFileTestGenerated extends AbstractJavaTo
             doTest(fileName);
         }
 
+        @TestMetadata("castNullObject.java")
+        public void testCastNullObject() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/typeCastExpression/castNullObject.java");
+            doTest(fileName);
+        }
+
         @TestMetadata("castNullable.java")
         public void testCastNullable() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("j2k/testData/fileOrElement/typeCastExpression/castNullable.java");