JAVA中使用双括号来初始化静态常量的小技巧

public static final Map<String, String> DATA = new TreeMap<String, String>();

static
{

DATA.put("a", "A");

//blah blah blah
}

public static final Map<String, String> DATA = new TreeMap<String, String>()
{{

this.put("a", "A");

//blah blah blah

}};