final的注意事项？

final被修饰的字符不能修改，final不能与static连用

楼上别误导别人
final 修饰符可以与static 同时使用的;
见java源码如下

[AppleScript] 纯文本查看 复制代码

    /**
     * The "standard" error output stream. This stream is already
     * open and ready to accept output data.
     * <p>
     * Typically this stream corresponds to display output or another
     * output destination specified by the host environment or user. By
     * convention, this output stream is used to display error messages
     * or other information that should come to the immediate attention
     * of a user even if the principal output stream, the value of the
     * variable <code>out</code>, has been redirected to a file or other
     * destination that is typically not continuously monitored.
     */
public final static PrintStream err = null;

final 和static 同时使用
此处是用于声明一个全局的不可更改的常量;
让使用者可以通过类名.来调用,
并且避免使用者通过某些方式对其更改,导致程序的后续运行出错.
有时候有些常量在当前类中使用频率较高;
或者是其调用者的使用频率较高,用final static 声明一个常量,可以编写代码的效率;
如数学中的PI;
若是,将其使用一次,便输入一次,是十分麻烦的,

[AppleScript] 纯文本查看 复制代码

    
/**
     * The {@code double} value that is closer than any other to
     * <i>pi</i>, the ratio of the circumference of a circle to its
     * diameter.
     */
    public static final double PI = 3.14159265358979323846;

final可以和static连用，public static final a =0;是定义全局静态变量a的，final修饰方法不能被重写，修饰类不能被继承