Use final.

Author: garydgregory

src/main/java/org/apache/commons/cli/Option.java

@@ -187,7 +187,7 @@ public Builder numberOfArgs(final int numberOfArgs) {
          * @throws IllegalArgumentException if there are any non valid Option characters in {@code opt}
          * @since 1.5.0
          */
-        public Builder option(String option) throws IllegalArgumentException {
+        public Builder option(final String option) throws IllegalArgumentException {
             this.option = OptionValidator.validate(option);
             return this;
         }

src/test/java/org/apache/commons/cli/HelpFormatterTest.java

@@ -339,7 +339,7 @@ public void testPrintHelpNewlineHeader() {
             0,
             "footer" + EOL
         );
-        String expected = "usage: test" + EOL +
+        final String expected = "usage: test" + EOL +
                           EOL +
                           "-ab" + EOL +
                           "footer" + EOL;