Use final.
diff --git a/commons-numbers-complex/src/main/java/org/apache/commons/numbers/complex/Complex.java b/commons-numbers-complex/src/main/java/org/apache/commons/numbers/complex/Complex.java
index 33e8a4d..cae5385 100644
--- a/commons-numbers-complex/src/main/java/org/apache/commons/numbers/complex/Complex.java
+++ b/commons-numbers-complex/src/main/java/org/apache/commons/numbers/complex/Complex.java
@@ -2829,8 +2829,8 @@
         }
 
         // Compute with positive values and determine sign at the end
-        double x = Math.abs(real);
-        double y = Math.abs(imaginary);
+        final double x = Math.abs(real);
+        final double y = Math.abs(imaginary);
 
         // Compute
         double t;