Add missing @Override tags, add final for member variables where applicable.

src/main/java/org/apache/commons/math4/exception/MathArithmeticException.java

@@ -58,6 +58,7 @@ public class MathArithmeticException extends ArithmeticException
     }
 
     /** {@inheritDoc} */
+    @Override
     public ExceptionContext getContext() {
         return context;
     }

src/main/java/org/apache/commons/math4/exception/MathIllegalArgumentException.java

@@ -46,6 +46,7 @@ public class MathIllegalArgumentException extends IllegalArgumentException
     }
 
     /** {@inheritDoc} */
+    @Override
     public ExceptionContext getContext() {
         return context;
     }

src/main/java/org/apache/commons/math4/exception/MathIllegalStateException.java

@@ -70,6 +70,7 @@ public class MathIllegalStateException extends IllegalStateException
     }
 
     /** {@inheritDoc} */
+    @Override
     public ExceptionContext getContext() {
         return context;
     }

src/main/java/org/apache/commons/math4/exception/MathRuntimeException.java

@@ -47,6 +47,7 @@ public class MathRuntimeException extends RuntimeException
     }
 
     /** {@inheritDoc} */
+    @Override
     public ExceptionContext getContext() {
         return context;
     }

src/main/java/org/apache/commons/math4/exception/MathUnsupportedOperationException.java

@@ -54,6 +54,7 @@ public class MathUnsupportedOperationException extends UnsupportedOperationExcep
     }
 
     /** {@inheritDoc} */
+    @Override
     public ExceptionContext getContext() {
         return context;
     }

src/main/java/org/apache/commons/math4/exception/NullArgumentException.java

@@ -59,11 +59,12 @@ public class NullArgumentException extends NullPointerException
         context = new ExceptionContext(this);
         context.addMessage(pattern, arguments);
     }
-    
+
     /**
      * {@inheritDoc}
      * @since 4.0
      */
+    @Override
     public ExceptionContext getContext() {
         return context;
     }

src/main/java/org/apache/commons/math4/exception/util/DummyLocalizable.java

@@ -39,11 +39,13 @@ public class DummyLocalizable implements Localizable {
     }
 
     /** {@inheritDoc} */
+    @Override
     public String getSourceString() {
         return source;
     }
 
     /** {@inheritDoc} */
+    @Override
     public String getLocalizedString(Locale locale) {
         return source;
     }

src/main/java/org/apache/commons/math4/exception/util/LocalizedFormats.java

@@ -379,11 +379,13 @@ public enum LocalizedFormats implements Localizable {
     }
 
     /** {@inheritDoc} */
+    @Override
     public String getSourceString() {
         return sourceFormat;
     }
 
     /** {@inheritDoc} */
+    @Override
     public String getLocalizedString(final Locale locale) {
         try {
             final String path = LocalizedFormats.class.getName().replaceAll("\\.", "/");