diff --git a/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java b/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
index 64340ceb16a..6ca20a702a8 100644
--- a/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
+++ b/idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
@@ -796,6 +796,13 @@ public class ExpressionCodegen extends JetVisitor {
         }
         if (type instanceof PsiClassType) {
             PsiClass psiClass = ((PsiClassType) type).resolve();
+            if (psiClass instanceof PsiTypeParameter) {
+                final PsiClassType[] extendsListTypes = psiClass.getExtendsListTypes();
+                if (extendsListTypes.length > 0) {
+                    throw new UnsupportedOperationException("should return common supertype");
+                }
+                return OBJECT_TYPE;
+            }
             if (psiClass == null) {
                 throw new UnsupportedOperationException("unresolved PsiClassType: " + type);
             }
diff --git a/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java b/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java
index 2414093a025..71c516ba0c2 100644
--- a/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java
+++ b/idea/src/org/jetbrains/jet/codegen/JetTypeMapper.java
@@ -3,7 +3,6 @@ package org.jetbrains.jet.codegen;
 import com.intellij.psi.PsiClass;
 import com.intellij.psi.PsiElement;
 import jet.typeinfo.TypeInfo;
-import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.descriptors.*;
 import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.BindingContext;
@@ -33,7 +32,11 @@ public class JetTypeMapper {
     }
 
     static String jvmName(PsiClass psiClass) {
-        return psiClass.getQualifiedName().replace(".", "/");
+        final String qName = psiClass.getQualifiedName();
+        if (qName == null) {
+            throw new UnsupportedOperationException("can't evaluate JVM name for anonymous class " + psiClass);
+        }
+        return qName.replace(".", "/");
     }
 
     public String jvmName(ClassDescriptor jetClass, OwnerKind kind) {
diff --git a/idea/tests/org/jetbrains/jet/codegen/NamespaceGenTest.java b/idea/tests/org/jetbrains/jet/codegen/NamespaceGenTest.java
index 675ec2ee193..ef29499407c 100644
--- a/idea/tests/org/jetbrains/jet/codegen/NamespaceGenTest.java
+++ b/idea/tests/org/jetbrains/jet/codegen/NamespaceGenTest.java
@@ -385,4 +385,12 @@ public class NamespaceGenTest extends CodegenTestCase {
         assertTrue(result.contains(10));
         assertFalse(result.contains(11));
     }
+
+    public void testSubstituteJavaMethodTypeParameters() throws Exception {
+        loadText("import java.util.*; fun foo(l: ArrayList<Int>) { l.add(10) }");
+        final Method main = generateFunction();
+        final ArrayList<Integer> l = new ArrayList<Integer>();
+        main.invoke(null, l);
+        assertEquals(10, l.get(0).intValue());
+    }
 }