diff --git a/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java b/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
index 9f6577ebe63..08ed66ffaee 100644
--- a/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
+++ b/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
@@ -344,7 +344,7 @@ public class ExpressionCodegen extends JetVisitor {
         }
     }
 
-    private String getMethodDescriptor(PsiMethod method) {
+    private static String getMethodDescriptor(PsiMethod method) {
         Type returnType = psiTypeToAsm(method.getReturnType());
         PsiParameter[] parameters = method.getParameterList().getParameters();
         Type[] parameterTypes = new Type[parameters.length];
@@ -354,7 +354,7 @@ public class ExpressionCodegen extends JetVisitor {
         return Type.getMethodDescriptor(returnType, parameterTypes);
     }
 
-    private Type psiTypeToAsm(PsiType type) {
+    private static Type psiTypeToAsm(PsiType type) {
         if (type instanceof PsiPrimitiveType) {
             if (type == PsiType.VOID) {
                 return Type.VOID_TYPE;
@@ -368,6 +368,21 @@ public class ExpressionCodegen extends JetVisitor {
             if (type == PsiType.BOOLEAN) {
                 return Type.BOOLEAN_TYPE;
             }
+            if (type == PsiType.BYTE) {
+                return Type.BYTE_TYPE;
+            }
+            if (type == PsiType.SHORT) {
+                return Type.SHORT_TYPE;
+            }
+            if (type == PsiType.CHAR) {
+                return Type.CHAR_TYPE;
+            }
+            if (type == PsiType.FLOAT) {
+                return Type.FLOAT_TYPE;
+            }
+            if (type == PsiType.DOUBLE) {
+                return Type.DOUBLE_TYPE;
+            }
         }
         if (type instanceof PsiClassType) {
             PsiClass psiClass = ((PsiClassType) type).resolve();
diff --git a/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java b/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java
index c9ec7b4b12f..1b1abb1c0b5 100644
--- a/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java
+++ b/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java
@@ -65,7 +65,7 @@ public class JetTypeMapper {
         if (jetType.equals(TypeUtils.makeNullable(standardLibrary.getBooleanType()))) {
             return Type.getObjectType("java/lang/Boolean");
         }
-        if (jetType.equals(standardLibrary.getStringType())) {
+        if (jetType.equals(standardLibrary.getStringType()) || jetType.equals(standardLibrary.getNullableStringType())) {
             return Type.getType(String.class);
         }
 
diff --git a/idea/tests/org/jetbrains/jet/codegen/NamespaceGenTest.java b/idea/tests/org/jetbrains/jet/codegen/NamespaceGenTest.java
index 3d2a3f34b53..a0719af4887 100644
--- a/idea/tests/org/jetbrains/jet/codegen/NamespaceGenTest.java
+++ b/idea/tests/org/jetbrains/jet/codegen/NamespaceGenTest.java
@@ -308,6 +308,12 @@ public class NamespaceGenTest extends LightCodeInsightFixtureTestCase {
         binOpTest("fun foo(a: Double, b: Double): Boolean = a == b", 1.0, 2.0, false);
     }
 
+    public void testDoubleToJava() throws Exception {
+        loadText("fun foo(d: Double): String? = Double.toString(d)");
+        final Method main = generateFunction();
+        assertEquals("1.0", main.invoke(null, 1.0));
+    }
+
     private void binOpTest(final String text, final Object arg1, final Object arg2, final Object expected) throws Exception {
         loadText(text);
         System.out.println(generateToText());