Type mismatch: cannot convert from element type Object to String 解决办法

首先放上我的源码，看看你的代码是不是我这个类似的。

 @Test
     void predicateTest() throws Exception {
         List<String> languages = Arrays.asList("Java", "Scala", "C++", "Haskell", "Lisp");
         System.out.println("Languages which starts with J :");
         filter(languages, (str) -> ((String) str).startsWith("J"));
         System.out.println("Languages which ends with a ");
         filter(languages, (str) -> ((String) str).endsWith("a"));
         System.out.println("Print all languages :");
         filter(languages, (str) -> true);
         System.out.println("Print no language : ");
         filter(languages, (str) -> false);
         System.out.println("Print language whose length greater than 4:");
         filter(languages, (str) -> ((String) str).length() > 4);
     }

     public static void filter(List names, Predicate condition) {
         for (String name : names) {
             if (condition.test(name)) {
                 System.out.println(name + " ");
             }
         }
     }

存在问题截图

解决办法