Type mismatch: cannot convert from element type Object to String 解決辦法

首先放上我的源碼，看看你的代碼是不是我這個類似的。

@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 + " ");
            }
        }
    }

存在問題截圖

解決辦法