{
        List list = new ArrayList() {{
            add("25");
            add("39");
            add("5");
            add("40");
            add("39");
            add("25");
        }};

        System.out.println("list = " + list.toString());  //list = [25, 39, 5, 40, 39, 25]


    }

打印的不是地址池,可以放心使用

Java的List toString问题_java

jdk自己重写了toString逻辑:

源码: java.util.AbstractCollection#toString 方法

public String toString() {
        Iterator<E> it = iterator();
        if (! it.hasNext())
            return "[]";

        StringBuilder sb = new StringBuilder();
        sb.append('[');
        for (;;) {
            E e = it.next();
            sb.append(e == this ? "(this Collection)" : e);
            if (! it.hasNext())
                return sb.append(']').toString();
            sb.append(',').append(' ');
        }
    }