diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/GroovyPsiElementFactory.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/GroovyPsiElementFactory.java
index 0f0b209d4511..74ce1e824592 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/GroovyPsiElementFactory.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/GroovyPsiElementFactory.java
@@ -98,13 +98,13 @@ public abstract class GroovyPsiElementFactory {
     return createReferenceElementFromText(refName, null);
   }
 
-  public abstract GrCodeReferenceElement createReferenceElementFromText(String refName, PsiElement context);
+  public abstract GrCodeReferenceElement createReferenceElementFromText(String refName, @Nullable PsiElement context);
 
   public GrExpression createExpressionFromText(String exprText) {
     return createExpressionFromText(exprText, null);
   }
 
-  public abstract GrExpression createExpressionFromText(String exprText, PsiElement context);
+  public abstract GrExpression createExpressionFromText(String exprText, @Nullable PsiElement context);
 
   public abstract GrVariableDeclaration createFieldDeclaration(String[] modifiers, String identifier, GrExpression initializer, PsiType type);
   public abstract GrVariableDeclaration createFieldDeclarationFromText(String text);
@@ -126,13 +126,13 @@ public abstract class GroovyPsiElementFactory {
 
   public abstract GrClosableBlock createClosureFromText(String s) throws IncorrectOperationException;
 
-  public GrParameter createParameter(String name, @Nullable String typeText, GroovyPsiElement context) throws IncorrectOperationException {
+  public GrParameter createParameter(String name, @Nullable String typeText, @Nullable GroovyPsiElement context) throws IncorrectOperationException {
     return createParameter(name, typeText, null, context);
   }
 
   public abstract GrParameter createParameter(String name,
                                               @Nullable String typeText,
-                                              String initializer,
+                                              @Nullable String initializer,
                                               GroovyPsiElement context) throws IncorrectOperationException;
 
   public abstract GrCodeReferenceElement createTypeOrPackageReference(String qName);
@@ -146,7 +146,7 @@ public abstract class GroovyPsiElementFactory {
     return createTypeElement(typeText, null);
   }
 
-  public abstract GrTypeElement createTypeElement(String typeText, PsiElement context);
+  public abstract GrTypeElement createTypeElement(String typeText, @Nullable PsiElement context);
 
   public abstract GrParenthesizedExpression createParenthesizedExpr(GrExpression newExpr);
 
@@ -162,7 +162,7 @@ public abstract class GroovyPsiElementFactory {
 
   public abstract PsiElement createDotToken(String newDot);
 
-  public abstract GrMethod createMethodFromText(String methodText, PsiElement context);
+  public abstract GrMethod createMethodFromText(String methodText, @Nullable PsiElement context);
 
   public GrMethod createMethodFromText(String methodText) {
     return createMethodFromText(methodText, null);
@@ -170,7 +170,7 @@ public abstract class GroovyPsiElementFactory {
 
   public abstract GrAnnotation createAnnotationFromText(String annoText);
 
-  public abstract GroovyFile createGroovyFile(String text, boolean isPhisical, PsiElement context);
+  public abstract GroovyFile createGroovyFile(String text, boolean isPhysical, PsiElement context);
 
   public abstract GrMethod createMethodFromText(String modifier, String name, String type, String[] paramTypes, PsiElement context);
 
@@ -178,7 +178,7 @@ public abstract class GroovyPsiElementFactory {
                                                      String[] paramTypes,
                                                      String[] paramNames,
                                                      String body,
-                                                     PsiElement context);
+                                                     @Nullable PsiElement context);
 
   public GrMethod createConstructorFromText(@NotNull String constructorName, String[] paramTypes, String[] paramNames, String body) {
     return createConstructorFromText(constructorName, paramTypes, paramNames, body, null);
diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/GroovyPsiElementFactoryImpl.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/GroovyPsiElementFactoryImpl.java
index 84e48f951fc8..fced0e02fd4e 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/GroovyPsiElementFactoryImpl.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/GroovyPsiElementFactoryImpl.java
@@ -147,7 +147,7 @@ public class GroovyPsiElementFactoryImpl extends GroovyPsiElementFactory {
   public GrExpression createExpressionFromText(String text, PsiElement context) {
     GroovyFileImpl file = (GroovyFileImpl)createGroovyFile(text, false, context);
     assert file.getTopStatements()[0] instanceof GrExpression;
-    return (GrExpression) ((GroovyFileBase) file).getTopStatements()[0];
+    return (GrExpression) file.getTopStatements()[0];
   }
 
   public GrVariableDeclaration createVariableDeclaration(@Nullable String[] modifiers,
@@ -182,6 +182,7 @@ public class GroovyPsiElementFactoryImpl extends GroovyPsiElementFactory {
           !GroovyConfigUtils.getInstance().isVersionAtLeast(initializer, GroovyConfigUtils.GROOVY1_8)) {
         initializer = createMethodCallByAppCall((GrApplicationStatement)initializer);
       }
+      assert initializer != null;
       text.append(" = ").append(initializer.getText());
     }
 
@@ -399,7 +400,7 @@ public class GroovyPsiElementFactoryImpl extends GroovyPsiElementFactory {
     return ((GrLabeledStatement)definition).getLabel();
   }
 
-  public GrMethod createMethodFromText(@NotNull String methodText, PsiElement context) {
+  public GrMethod createMethodFromText(@NotNull String methodText, @Nullable PsiElement context) {
     GroovyFileImpl file = createDummyFile(methodText);
     if (context != null) {
       file.setContext(context);
@@ -424,7 +425,7 @@ public class GroovyPsiElementFactoryImpl extends GroovyPsiElementFactory {
     return createGroovyFile(idText, false, null);
   }
 
-  public GroovyFile createGroovyFile(String idText, boolean isPhysical, PsiElement context) {
+  public GroovyFile createGroovyFile(String idText, boolean isPhysical, @Nullable PsiElement context) {
     GroovyFileImpl file = createDummyFile(idText, isPhysical);
     file.setContext(context);
     return file;
@@ -519,12 +520,12 @@ public class GroovyPsiElementFactoryImpl extends GroovyPsiElementFactory {
   }
 
 
-  private static String generateMethodText(String modifier,
+  private static String generateMethodText(@Nullable String modifier,
                                            String name,
-                                           String type,
+                                           @Nullable String type,
                                            String[] paramTypes,
                                            String[] paramNames,
-                                           String body,
+                                           @Nullable String body,
                                            boolean isConstructor) {
     StringBuilder builder = new StringBuilder();
 
@@ -590,8 +591,6 @@ public class GroovyPsiElementFactoryImpl extends GroovyPsiElementFactory {
   }
 
   public GrDocComment createDocCommentFromText(String text) {
-    StringBuilder builder = new StringBuilder();
-    builder.append(text);
     return (GrDocComment)createGroovyFile(text).getFirstChild();
   }