diff --git a/java/java-psi-api/src/com/intellij/psi/PsiConstantEvaluationHelper.java b/java/java-psi-api/src/com/intellij/psi/PsiConstantEvaluationHelper.java
index 290d1bf11b70..9ae663ea3174 100644
--- a/java/java-psi-api/src/com/intellij/psi/PsiConstantEvaluationHelper.java
+++ b/java/java-psi-api/src/com/intellij/psi/PsiConstantEvaluationHelper.java
@@ -15,6 +15,7 @@
  */
 package com.intellij.psi;
 
+import com.intellij.psi.util.ConstantEvaluationOverflowException;
 import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.Nullable;
 
@@ -24,7 +25,7 @@ import java.util.concurrent.ConcurrentMap;
  * Service for evaluating values of constant expressions.
  *
  * @author ven
- * @see com.intellij.psi.JavaPsiFacade#getConstantEvaluationHelper()
+ * @see JavaPsiFacade#getConstantEvaluationHelper()
  */
 public abstract class PsiConstantEvaluationHelper {
   /**
@@ -35,22 +36,22 @@ public abstract class PsiConstantEvaluationHelper {
    */
   @Nullable
   @Contract("null -> null")
-  public Object computeConstantExpression(PsiElement expression) {
+  public Object computeConstantExpression(@Nullable PsiElement expression) {
     return computeConstantExpression(expression, false);
   }
 
   /**
    * Evaluates the value of the specified expression and optionally throws
-   * {@link com.intellij.psi.util.ConstantEvaluationOverflowException} if an overflow is detected
+   * {@link ConstantEvaluationOverflowException} if an overflow is detected
    * during the evaluation.
    *
    * @param expression the expression to evaluate.
    * @param throwExceptionOnOverflow if true, an exception is thrown if an overflow is detected during the evaluation.
    * @return the result of the evaluation, or null if the expression is not a constant expression.
    */
-  public abstract Object computeConstantExpression(PsiElement expression, boolean throwExceptionOnOverflow);
+  public abstract Object computeConstantExpression(@Nullable PsiElement expression, boolean throwExceptionOnOverflow);
 
-  public abstract Object computeExpression(PsiExpression expression, boolean throwExceptionOnOverflow,
+  public abstract Object computeExpression(@Nullable PsiExpression expression, boolean throwExceptionOnOverflow,
                                            @Nullable final AuxEvaluator auxEvaluator);
 
   public interface AuxEvaluator {